XML - DTD Exercises

countries.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE countries [
  <!ELEMENT countries (country*)>
  <!ELEMENT country ((language|city)*)>
  <!ATTLIST country name CDATA #REQUIRED population CDATA #REQUIRED area CDATA #REQUIRED>
  <!ELEMENT language (#PCDATA)>
  <!ATTLIST language percentage CDATA #REQUIRED>
  <!ELEMENT city (name, population)>
  <!ELEMENT name (#PCDATA)>
  <!ELEMENT population (#PCDATA)>
]>

<countries>
  <country name="Afghanistan" population="22664136" area="647500">
    <language percentage="11">Turkic</language>
    <language percentage="35">Pashtu</language>
    <language percentage="50">Afghan Persian</language>
  </country>
  <country name="Albania" population="3249136" area="28750"/>
  <country name="Algeria" population="29183032" area="2381740">
    <city>
      <name>Algiers</name>
      <population>1507241</population>
    </city>
  </country>
  <country name="American Samoa" population="59566" area="199"/>
  <country name="Andorra" population="72766" area="450"/>
  <country name="Angola" population="10342899" area="1246700"/>
  <country name="Anguilla" population="10424" area="91">
    <language percentage="100">English</language>
  </country>
  <country name="Antigua and Barbuda" population="65647" area="440">
    <language percentage="100">English</language>
  </country>
  <country name="Argentina" population="34672996" area="2766890">
    <city>
      <name>La Matanza</name>
      <population>1111811</population>
    </city>
    <city>
      <name>Cordoba</name>
      <population>1208713</population>
    </city>
    <city>
      <name>Rosario</name>
      <population>1118984</population>
    </city>
    <city>
      <name>Buenos Aires</name>
      <population>2988006</population>
    </city>
  </country>
  <country name="Armenia" population="3463574" area="29800">
    <city>
      <name>Yerevan</name>
      <population>1200000</population>
    </city>
    <language percentage="2">Russian</language>
    <language percentage="96">Armenian</language>
  </country>
  <country name="Aruba" population="67794" area="193"/>
  <country name="Australia" population="18260864" area="7686850">
    <city>
      <name>Sydney</name>
      <population>3657000</population>
    </city>
    <city>
      <name>Brisbane</name>
      <population>1302000</population>
    </city>
    <city>
      <name>Adelaide</name>
      <population>1050000</population>
    </city>
    <city>
      <name>Melbourne</name>
      <population>3081000</population>
    </city>
    <city>
      <name>Perth</name>
      <population>1193000</population>
    </city>
    <language percentage="100">English</language>
  </country>
  <country name="Austria" population="8023244" area="83850">
    <city>
      <name>Vienna</name>
      <population>1583000</population>
    </city>
    <language percentage="100">German</language>
  </country>
  <country name="Azerbaijan" population="7676953" area="86600">
    <city>
      <name>Baku</name>
      <population>1740000</population>
    </city>
    <language percentage="3">Russian</language>
    <language percentage="2">Armenian</language>
    <language percentage="89">Azeri</language>
  </country>
  <country name="Bahamas" population="259367" area="13940"/>
  <country name="Bahrain" population="590042" area="620"/>
  <country name="Bangladesh" population="123062800" area="144000">
    <city>
      <name>Dhaka</name>
      <population>3839000</population>
    </city>
    <city>
      <name>Chittagong</name>
      <population>1599000</population>
    </city>
  </country>
  <country name="Barbados" population="257030" area="430">
    <language percentage="100">English</language>
  </country>
  <country name="Belarus" population="10415973" area="207600">
    <city>
      <name>Minsk</name>
      <population>1540000</population>
    </city>
  </country>
  <country name="Belgium" population="10170241" area="30510">
    <language percentage="32">French</language>
    <language percentage="1">German</language>
    <language percentage="56">Dutch</language>
  </country>
  <country name="Belize" population="219296" area="22960"/>
  <country name="Benin" population="5709529" area="112620"/>
  <country name="Bermuda" population="62099" area="50">
    <language percentage="100">English</language>
  </country>
  <country name="Bhutan" population="1822625" area="47000"/>
  <country name="Bolivia" population="7165257" area="1098580"/>
  <country name="Bosnia and Herzegovina" population="2656240" area="51233">
    <language percentage="99">Serbo-Croatian</language>
  </country>
  <country name="Botswana" population="1477630" area="600370"/>
  <country name="Brazil" population="162661216" area="8511965">
    <city>
      <name>Manaus</name>
      <population>1158265</population>
    </city>
    <city>
      <name>Salvador</name>
      <population>2209465</population>
    </city>
    <city>
      <name>Fortaleza</name>
      <population>1967365</population>
    </city>
    <city>
      <name>Belo Horizonte</name>
      <population>2091770</population>
    </city>
    <city>
      <name>Belem</name>
      <population>1142258</population>
    </city>
    <city>
      <name>Curitiba</name>
      <population>1465698</population>
    </city>
    <city>
      <name>Recife</name>
      <population>1342877</population>
    </city>
    <city>
      <name>Rio de Janeiro</name>
      <population>5533011</population>
    </city>
    <city>
      <name>Porto Alegre</name>
      <population>1286251</population>
    </city>
    <city>
      <name>Sao Paulo</name>
      <population>9811776</population>
    </city>
    <city>
      <name>Brasilia</name>
      <population>1817001</population>
    </city>
  </country>
  <country name="British Virgin Islands" population="13195" area="150">
    <language percentage="100">English</language>
  </country>
  <country name="Brunei" population="299939" area="5770"/>
  <country name="Bulgaria" population="8612757" area="110910">
    <city>
      <name>Sofia</name>
      <population>1300000</population>
    </city>
    <language percentage="100">Bulgarian</language>
  </country>
  <country name="Burkina Faso" population="10623323" area="274200"/>
  <country name="Burma" population="45975624" area="678500">
    <city>
      <name>Rangoon</name>
      <population>2513000</population>
    </city>
    <language percentage="100">Burmese</language>
  </country>
  <country name="Burundi" population="5943057" area="27830"/>
  <country name="Cambodia" population="10861218" area="181040"/>
  <country name="Cameroon" population="14261557" area="475440"/>
  <country name="Canada" population="28820672" area="9976140">
    <city>
      <name>Montreal</name>
      <population>1017666</population>
    </city>
  </country>
  <country name="Cape Verde" population="449066" area="4030"/>
  <country name="Cayman Islands" population="34646" area="260">
    <language percentage="100">English</language>
  </country>
  <country name="Central African Republic" population="3274426" area="622980"/>
  <country name="Chad" population="6976845" area="1284000"/>
  <country name="Chile" population="14333258" area="756950">
    <city>
      <name>Santiago</name>
      <population>4318000</population>
    </city>
    <language percentage="100">Spanish</language>
  </country>
  <country name="China" population="1210004992" area="9596960">
    <city>
      <name>Hong Kong</name>
      <population>6218000</population>
    </city>
    <city>
      <name>Hefei</name>
      <population>1000000</population>
    </city>
    <city>
      <name>Huainan</name>
      <population>1200000</population>
    </city>
    <city>
      <name>Lanzhou</name>
      <population>1510000</population>
    </city>
    <city>
      <name>Guangzhou</name>
      <population>3580000</population>
    </city>
    <city>
      <name>Guiyang</name>
      <population>1530000</population>
    </city>
    <city>
      <name>Shijiazhuang</name>
      <population>1320000</population>
    </city>
    <city>
      <name>Tangshan</name>
      <population>1500000</population>
    </city>
    <city>
      <name>Handan</name>
      <population>1110000</population>
    </city>
    <city>
      <name>Harbin</name>
      <population>2830000</population>
    </city>
    <city>
      <name>Qiqihar</name>
      <population>1380000</population>
    </city>
    <city>
      <name>Zhengzhou</name>
      <population>1710000</population>
    </city>
    <city>
      <name>Luoyang</name>
      <population>1190000</population>
    </city>
    <city>
      <name>Wuhan</name>
      <population>3750000</population>
    </city>
    <city>
      <name>Changsha</name>
      <population>1330000</population>
    </city>
    <city>
      <name>Nanjing</name>
      <population>2500000</population>
    </city>
    <city>
      <name>Fuzhou</name>
      <population>1290000</population>
    </city>
    <city>
      <name>Nanchang</name>
      <population>1350000</population>
    </city>
    <city>
      <name>Jilin</name>
      <population>1270000</population>
    </city>
    <city>
      <name>Changchun</name>
      <population>2110000</population>
    </city>
    <city>
      <name>Shenyang</name>
      <population>4540000</population>
    </city>
    <city>
      <name>Dalian</name>
      <population>2400000</population>
    </city>
    <city>
      <name>Anshan</name>
      <population>1390000</population>
    </city>
    <city>
      <name>Fushun</name>
      <population>1350000</population>
    </city>
    <city>
      <name>Xian</name>
      <population>2760000</population>
    </city>
    <city>
      <name>Jinan</name>
      <population>2320000</population>
    </city>
    <city>
      <name>Zibo</name>
      <population>2460000</population>
    </city>
    <city>
      <name>Qingdao</name>
      <population>2060000</population>
    </city>
    <city>
      <name>Taiyuan</name>
      <population>1960000</population>
    </city>
    <city>
      <name>Datong</name>
      <population>1110000</population>
    </city>
    <city>
      <name>Chengdu</name>
      <population>2810000</population>
    </city>
    <city>
      <name>Chongqing</name>
      <population>2980000</population>
    </city>
    <city>
      <name>Kunming</name>
      <population>1520000</population>
    </city>
    <city>
      <name>Hangzhou</name>
      <population>1340000</population>
    </city>
    <city>
      <name>Ningbo</name>
      <population>1090000</population>
    </city>
    <city>
      <name>Nanning</name>
      <population>1070000</population>
    </city>
    <city>
      <name>Baotou</name>
      <population>1200000</population>
    </city>
    <city>
      <name>Urumqi</name>
      <population>1160000</population>
    </city>
    <city>
      <name>Beijing</name>
      <population>7000000</population>
    </city>
    <city>
      <name>Shanghai</name>
      <population>7830000</population>
    </city>
    <city>
      <name>Tianjin</name>
      <population>5770000</population>
    </city>
  </country>
  <country name="Christmas Island" population="813" area="135">
    <language percentage="100">English</language>
  </country>
  <country name="Cocos Islands" population="609" area="14">
    <language percentage="100">English</language>
  </country>
  <country name="Colombia" population="36813160" area="1138910">
    <city>
      <name>Medellin</name>
      <population>1621356</population>
    </city>
    <city>
      <name>Barranquilla</name>
      <population>1064255</population>
    </city>
    <city>
      <name>Bogota</name>
      <population>5237635</population>
    </city>
    <city>
      <name>Cali</name>
      <population>1718871</population>
    </city>
    <language percentage="100">Spanish</language>
  </country>
  <country name="Comoros" population="569237" area="2170"/>
  <country name="Congo" population="2527841" area="342000"/>
  <country name="Cook Islands" population="19561" area="240"/>
  <country name="Costa Rica" population="3463083" area="51100"/>
  <country name="Cote dIvoire" population="14762445" area="322460"/>
  <country name="Croatia" population="5004112" area="56538">
    <language percentage="96">Serbo-Croatian</language>
  </country>
  <country name="Cuba" population="10951334" area="110860">
    <city>
      <name>Havana</name>
      <population>2241000</population>
    </city>
    <language percentage="100">Spanish</language>
  </country>
  <country name="Cyprus" population="744609" area="9250"/>
  <country name="Czech Republic" population="10321120" area="78703">
    <city>
      <name>Prague</name>
      <population>1215000</population>
    </city>
  </country>
  <country name="Denmark" population="5249632" area="43070">
    <city>
      <name>Copenhagen</name>
      <population>1358540</population>
    </city>
  </country>
  <country name="Djibouti" population="427642" area="22000"/>
  <country name="Dominica" population="82926" area="750"/>
  <country name="Dominican Republic" population="8088881" area="48730">
    <city>
      <name>Santo Domingo</name>
      <population>1400000</population>
    </city>
    <language percentage="100">Spanish</language>
  </country>
  <country name="Ecuador" population="11466291" area="283560">
    <city>
      <name>Quito</name>
      <population>1200000</population>
    </city>
    <city>
      <name>Guayaquil</name>
      <population>1300868</population>
    </city>
  </country>
  <country name="Egypt" population="63575108" area="1001450">
    <city>
      <name>El Giza</name>
      <population>1671000</population>
    </city>
    <city>
      <name>Alexandria</name>
      <population>2917000</population>
    </city>
    <city>
      <name>Cairo</name>
      <population>6053000</population>
    </city>
  </country>
  <country name="El Salvador" population="5828987" area="21040"/>
  <country name="Equatorial Guinea" population="431282" area="28050"/>
  <country name="Eritrea" population="3427883" area="121320"/>
  <country name="Estonia" population="1459428" area="45100"/>
  <country name="Ethiopia" population="57171664" area="1127127">
    <city>
      <name>Addis Ababa</name>
      <population>2316400</population>
    </city>
  </country>
  <country name="Falkland Islands" population="2374" area="12170">
    <language percentage="100">English</language>
  </country>
  <country name="Faroe Islands" population="43857" area="1400"/>
  <country name="Fiji" population="782381" area="18270"/>
  <country name="Finland" population="5105230" area="337030">
    <language percentage="6.3">Swedish</language>
    <language percentage="93.5">Finnish</language>
  </country>
  <country name="France" population="58317448" area="547030">
    <city>
      <name>Paris</name>
      <population>2152423</population>
    </city>
    <language percentage="100">French</language>
  </country>
  <country name="French Guiana" population="151187" area="91000">
    <language percentage="100">French</language>
  </country>
  <country name="French Polynesia" population="224911" area="4167"/>
  <country name="Gabon" population="1172798" area="267670"/>
  <country name="Gambia" population="1204984" area="11300"/>
  <country name="Georgia" population="5219810" area="69700">
    <city>
      <name>Tbilisi</name>
      <population>1200000</population>
    </city>
    <language percentage="9">Russian</language>
    <language percentage="7">Armenian</language>
    <language percentage="6">Azeri</language>
    <language percentage="71">Georgian</language>
  </country>
  <country name="Germany" population="83536112" area="356910">
    <city>
      <name>Munchen</name>
      <population>1244676</population>
    </city>
    <city>
      <name>Muenchen</name>
      <population>1290079</population>
    </city>
    <city>
      <name>Berlin</name>
      <population>3472009</population>
    </city>
    <city>
      <name>Hamburg</name>
      <population>1705872</population>
    </city>
    <language percentage="100">German</language>
  </country>
  <country name="Ghana" population="17698272" area="238540"/>
  <country name="Gibraltar" population="28765" area="6.5"/>
  <country name="Greece" population="10538594" area="131940"/>
  <country name="Greenland" population="58203" area="2175600"/>
  <country name="Grenada" population="94961" area="340"/>
  <country name="Guadeloupe" population="407768" area="1780">
    <language percentage="99">French</language>
  </country>
  <country name="Guam" population="156974" area="541.3"/>
  <country name="Guatemala" population="11277614" area="108890">
    <language percentage="60">Spanish</language>
    <language percentage="40">Indian</language>
  </country>
  <country name="Guernsey" population="62920" area="194"/>
  <country name="Guinea" population="7411981" area="245860">
    <language percentage="100">French</language>
  </country>
  <country name="Guinea-Bissau" population="1151330" area="36120"/>
  <country name="Guyana" population="712091" area="214970"/>
  <country name="Haiti" population="6731539" area="27750">
    <language percentage="10">French</language>
  </country>
  <country name="Holy See" population="840" area="0.44"/>
  <country name="Honduras" population="5605193" area="112090"/>
  <country name="Hungary" population="10002541" area="93030">
    <city>
      <name>Budapest</name>
      <population>2016000</population>
    </city>
    <language percentage="98.2">Hungarian</language>
  </country>
  <country name="Iceland" population="270292" area="103000">
    <language percentage="100">Icelandic</language>
  </country>
  <country name="India" population="952107712" area="3287590">
    <city>
      <name>Hyderabad</name>
      <population>3145939</population>
    </city>
    <city>
      <name>Ahmadabad</name>
      <population>2954526</population>
    </city>
    <city>
      <name>Surat</name>
      <population>1505872</population>
    </city>
    <city>
      <name>Vadodara</name>
      <population>1061598</population>
    </city>
    <city>
      <name>Bangalore</name>
      <population>3302296</population>
    </city>
    <city>
      <name>Bhopal</name>
      <population>1062771</population>
    </city>
    <city>
      <name>Indore</name>
      <population>1091674</population>
    </city>
    <city>
      <name>Mumbai</name>
      <population>9925891</population>
    </city>
    <city>
      <name>Nagpur</name>
      <population>1624752</population>
    </city>
    <city>
      <name>Pune</name>
      <population>1566651</population>
    </city>
    <city>
      <name>Kalyan</name>
      <population>1014557</population>
    </city>
    <city>
      <name>Ludhiana</name>
      <population>1042740</population>
    </city>
    <city>
      <name>Jaipur</name>
      <population>1458183</population>
    </city>
    <city>
      <name>Madras</name>
      <population>3841396</population>
    </city>
    <city>
      <name>Lucknow</name>
      <population>1619115</population>
    </city>
    <city>
      <name>Kanpur</name>
      <population>1879420</population>
    </city>
    <city>
      <name>Calcutta</name>
      <population>4399819</population>
    </city>
    <city>
      <name>New Delhi</name>
      <population>7206704</population>
    </city>
    <language percentage="30">Hindi</language>
  </country>
  <country name="Indonesia" population="206611600" area="1919440">
    <city>
      <name>Jakarta</name>
      <population>8259266</population>
    </city>
    <city>
      <name>Bandung</name>
      <population>2058649</population>
    </city>
    <city>
      <name>Semarang</name>
      <population>1250971</population>
    </city>
    <city>
      <name>Surabaya</name>
      <population>2483871</population>
    </city>
    <city>
      <name>Palembang</name>
      <population>1144279</population>
    </city>
    <city>
      <name>Medan</name>
      <population>1730752</population>
    </city>
  </country>
  <country name="Iran" population="66094264" area="1648000">
    <city>
      <name>Tabriz</name>
      <population>1166203</population>
    </city>
    <city>
      <name>Esfahan</name>
      <population>1220595</population>
    </city>
    <city>
      <name>Shiraz</name>
      <population>1042801</population>
    </city>
    <city>
      <name>Mashhad</name>
      <population>1964489</population>
    </city>
    <city>
      <name>Tehran</name>
      <population>6750043</population>
    </city>
    <language percentage="1">Turkish</language>
    <language percentage="1">Baloch</language>
    <language percentage="9">Kurdish</language>
    <language percentage="1">Arabic</language>
    <language percentage="2">Luri</language>
    <language percentage="58">Persian Persian</language>
    <language percentage="26">Turkic Turkic</language>
  </country>
  <country name="Iraq" population="21422292" area="437072">
    <city>
      <name>Baghdad</name>
      <population>4478000</population>
    </city>
  </country>
  <country name="Ireland" population="3566833" area="70280"/>
  <country name="Israel" population="5421995" area="20770"/>
  <country name="Italy" population="57460272" area="301230">
    <city>
      <name>Milano</name>
      <population>1432184</population>
    </city>
    <city>
      <name>Rome</name>
      <population>2791354</population>
    </city>
    <city>
      <name>Napoli</name>
      <population>1206013</population>
    </city>
  </country>
  <country name="Jamaica" population="2595275" area="10990"/>
  <country name="Japan" population="125449704" area="377835">
    <city>
      <name>Sapporo</name>
      <population>1748000</population>
    </city>
    <city>
      <name>Tokyo</name>
      <population>7843000</population>
    </city>
    <city>
      <name>Yokohama</name>
      <population>3256000</population>
    </city>
    <city>
      <name>Kawasaki</name>
      <population>1187000</population>
    </city>
    <city>
      <name>Nagoya</name>
      <population>2108000</population>
    </city>
    <city>
      <name>Kyoto</name>
      <population>1415000</population>
    </city>
    <city>
      <name>Osaka</name>
      <population>2492000</population>
    </city>
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courses-ID.xml

<?xml version="1.0" ?>

<!DOCTYPE Course_Catalog [
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]>

<Course_Catalog>

  <Department Code="CS" Chair="JW">
    
    <Title>Computer Science</Title>

    <Course Number="CS106A" Instructors="JC ER MS" Enrollment="1070">
      <Title>Programming Methodology</Title>
      <Description>Introduction to the engineering of computer applications emphasizing modern software engineering principles.</Description>
    </Course>
    
    <Course Number="CS106B" Prerequisites="CS106A" Instructors="JC ER" Enrollment="620">
      <Title>Programming Abstractions</Title>
      <Description>Abstraction and its relation to programming.</Description>
    </Course>
  
    <Course Number="CS107" Prerequisites="CS106B" Instructors="JZ" Enrollment="500">
      <Title>Computer Organization and Systems</Title>
      <Description>Introduction to the fundamental concepts of computer systems.</Description>
    </Course>
  
    <Course Number="CS109" Prerequisites="CS106B" Instructors="MS" Enrollment="280">
      <Title>Introduction to Probability for Computer Scientists</Title>
    </Course>

    <Course Number="CS124" Prerequisites="CS107 CS109" Instructors="DJ" Enrollment="60">
      <Title>From Languages to Information</Title>
      <Description>Natural language processing. Cross-listed as <Courseref Number="LING180"/>.</Description>
    </Course>

    <Course Number="CS143" Prerequisites="CS107" Instructors="AA" Enrollment="90">
      <Title>Compilers</Title>
      <Description>Principles and practices for design and implementation of compilers and interpreters.</Description>
    </Course>
    
    <Course Number="CS145" Prerequisites="CS107" Instructors="JW" Enrollment="130">
      <Title>Introduction to Databases</Title>
      <Description>Database design and use of database management systems for applications.</Description>
    </Course>

    <Course Number="CS221" Prerequisites="CS107" Instructors="AN ST" Enrollment="180">
      <Title>Artificial Intelligence: Principles and Techniques</Title>
    </Course>
    
    <Course Number="CS228" Instructors="DK" Enrollment="110">
      <Title>Structured Probabilistic Models: Principles and Techniques</Title>
      <Description>Using probabilistic modeling languages to represent complex domains.</Description>
    </Course>

    <Course Number="CS229" Instructors="AN" Enrollment="320">
      <Title>Machine Learning</Title>
      <Description>A broad introduction to machine learning and statistical pattern recognition.</Description>
    </Course>
    
    <Professor InstrID="AA">
      <First_Name>Alex</First_Name>
      <Middle_Initial>S.</Middle_Initial>
      <Last_Name>Aiken</Last_Name>
    </Professor> 
    
    <Lecturer InstrID="JC">
      <First_Name>Jerry</First_Name>
      <Middle_Initial>R.</Middle_Initial>
      <Last_Name>Cain</Last_Name>
    </Lecturer>

    <Professor InstrID="DK">
      <First_Name>Daphne</First_Name>
      <Last_Name>Koller</Last_Name>
    </Professor>
    
    <Professor InstrID="AN">
      <First_Name>Andrew</First_Name>
      <Last_Name>Ng</Last_Name>
    </Professor>
    
    <Professor InstrID="ER">
      <First_Name>Eric</First_Name>
      <Last_Name>Roberts</Last_Name>
    </Professor>
    
    <Professor InstrID="MS">
      <First_Name>Mehran</First_Name>
      <Last_Name>Sahami</Last_Name>
    </Professor>
    
    <Professor InstrID="ST">
      <First_Name>Sebastian</First_Name>
      <Last_Name>Thrun</Last_Name>
    </Professor>    

    <Professor InstrID="JW">
      <First_Name>Jennifer</First_Name>
      <Last_Name>Widom</Last_Name>
    </Professor>

    <Lecturer InstrID="JZ">
      <First_Name>Julie</First_Name>
      <Last_Name>Zelenski</Last_Name>
    </Lecturer>
    
  </Department>

  <Department Code="EE" Chair="MH">
  
    <Title>Electrical Engineering</Title>
  
    <Course Number="EE108A" Instructors="SM">
      <Title>Digital Systems I</Title>
      <Description>Digital circuit, logic, and system design.</Description>
    </Course>
    
    <Course Number="EE108B" Prerequisites="EE108A CS106B" Instructors="WD OO">
      <Title>Digital Systems II</Title>
      <Description>The design of processor-based digital systems.</Description>
    </Course>

    <Professor InstrID="WD">
      <First_Name>William</First_Name>
      <Middle_Initial>J.</Middle_Initial>
      <Last_Name>Dally</Last_Name>
    </Professor>    
    
    <Professor InstrID="MH">
      <First_Name>Mark</First_Name>
      <Middle_Initial>A.</Middle_Initial>
      <Last_Name>Horowitz</Last_Name>    
    </Professor>
    
    <Professor InstrID="SM">
      <First_Name>Subhasish</First_Name>
      <Last_Name>Mitra</Last_Name>
    </Professor>
    
    <Professor InstrID="OO">
      <First_Name>Oyekunle</First_Name>
      <Last_Name>Olukotun</Last_Name>
    </Professor>
  
  </Department>

  <Department Code="LING" Chair="BL">
  
    <Title>Linguistics</Title>
    
    <Course Number="LING180" Prerequisites="CS107 CS109" Instructors="DJ" Enrollment="60">
      <Title>From Languages to Information</Title>
      <Description>Natural language processing. Cross-listed as <Courseref Number="CS124"/>.</Description>
    </Course>
    
    <Professor InstrID="DJ">
      <First_Name>Dan</First_Name>
      <Last_Name>Jurafsky</Last_Name>    
    </Professor>

    <Professor InstrID="BL">
      <First_Name>Beth</First_Name>
      <Last_Name>Levin</Last_Name>    
    </Professor>
    
  </Department>
  
</Course_Catalog>

courses-noID.xml

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<!DOCTYPE Course_Catalog [
  <!ELEMENT Course_Catalog (Department*)>
  <!ELEMENT Department (Title, Chair, Course+)>
  <!ATTLIST Department Code ID #REQUIRED>
  <!ELEMENT Title (#PCDATA)>
  <!ELEMENT Chair (Professor+)>
  <!ELEMENT Professor (First_Name, Middle_Initial?, Last_Name)>
  <!ELEMENT First_Name (#PCDATA)>
  <!ELEMENT Middle_Initial (#PCDATA)>
  <!ELEMENT Last_Name (#PCDATA)>
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  <!ATTLIST Course Number ID #REQUIRED Enrollment CDATA #IMPLIED>
  <!ELEMENT Description (#PCDATA)>
  <!ELEMENT Instructors (Professor|Lecturer)*>
  <!ELEMENT Lecturer (First_Name, Middle_Initial?, Last_Name)>
  <!ELEMENT Prerequisites (Prereq+)>
  <!ELEMENT Prereq (#PCDATA)>
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<Course_Catalog>

  <Department Code="CS">
    
    <Title>Computer Science</Title>
    
    <Chair>
      <Professor>
        <First_Name>Jennifer</First_Name>
        <Last_Name>Widom</Last_Name>
      </Professor>
    </Chair>

    <Course Number="CS106A" Enrollment="1070">
      <Title>Programming Methodology</Title>
      <Description>Introduction to the engineering of computer applications emphasizing modern software engineering principles.</Description>
      <Instructors>
        <Lecturer>
          <First_Name>Jerry</First_Name>
          <Middle_Initial>R.</Middle_Initial>
          <Last_Name>Cain</Last_Name>
        </Lecturer>
        <Professor>
          <First_Name>Eric</First_Name>
          <Last_Name>Roberts</Last_Name>
        </Professor>
        <Professor>
          <First_Name>Mehran</First_Name>
          <Last_Name>Sahami</Last_Name>
        </Professor>
      </Instructors>
    </Course>
    
    <Course Number="CS106B" Enrollment="620">
      <Title>Programming Abstractions</Title>
      <Description>Abstraction and its relation to programming.</Description>
      <Instructors>
        <Professor>
          <First_Name>Eric</First_Name>
          <Last_Name>Roberts</Last_Name>
        </Professor>
        <Lecturer>
          <First_Name>Jerry</First_Name>
          <Middle_Initial>R.</Middle_Initial>
          <Last_Name>Cain</Last_Name>
        </Lecturer>
      </Instructors>
      <Prerequisites>
        <Prereq>CS106A</Prereq>
      </Prerequisites>
    </Course>
    
    <Course Number="CS107" Enrollment="500">
      <Title>Computer Organization and Systems</Title>
      <Description>Introduction to the fundamental concepts of computer systems.</Description>
      <Instructors>
        <Lecturer>
          <First_Name>Julie</First_Name>
          <Last_Name>Zelenski</Last_Name>
        </Lecturer>
      </Instructors>
      <Prerequisites>
        <Prereq>CS106B</Prereq>
      </Prerequisites>
    </Course>    
  
    <Course Number="CS109" Enrollment="280">
      <Title>Introduction to Probability for Computer Scientists</Title>
      <Instructors>
        <Professor>
          <First_Name>Mehran</First_Name>
          <Last_Name>Sahami</Last_Name>
        </Professor>
      </Instructors>
      <Prerequisites>
        <Prereq>CS106B</Prereq>
      </Prerequisites>      
    </Course>

    <Course Number="CS124" Enrollment="60">
      <Title>From Languages to Information</Title>
      <Description>Natural language processing. Cross-listed as LING180.</Description>
      <Instructors>
        <Professor>
          <First_Name>Dan</First_Name>
          <Last_Name>Jurafsky</Last_Name>    
        </Professor>
      </Instructors>
      <Prerequisites>
        <Prereq>CS107</Prereq>
        <Prereq>CS109</Prereq>
      </Prerequisites>   
    </Course>

    <Course Number="CS143" Enrollment="90">
      <Title>Compilers</Title>
      <Description>Principles and practices for design and implementation of compilers and interpreters.</Description>
      <Instructors>
        <Professor>
          <First_Name>Alex</First_Name>
          <Middle_Initial>S.</Middle_Initial>
          <Last_Name>Aiken</Last_Name>    
        </Professor>
      </Instructors>
      <Prerequisites>
        <Prereq>CS107</Prereq>
      </Prerequisites>   
    </Course>
    
    <Course Number="CS145" Enrollment="130">
      <Title>Introduction to Databases</Title>
      <Description>Database design and use of database management systems for applications.</Description>
      <Instructors>
        <Professor>
          <First_Name>Jennifer</First_Name>
          <Last_Name>Widom</Last_Name>    
        </Professor>
      </Instructors>
      <Prerequisites>
        <Prereq>CS107</Prereq>
      </Prerequisites>  
    </Course>

    <Course Number="CS221" Enrollment="180">
      <Title>Artificial Intelligence: Principles and Techniques</Title>
      <Instructors>
        <Professor>
          <First_Name>Andrew</First_Name>
          <Last_Name>Ng</Last_Name>    
        </Professor>
        <Professor>
          <First_Name>Sebastian</First_Name>
          <Last_Name>Thrun</Last_Name>    
        </Professor>        
      </Instructors>
    </Course>
    
    <Course Number="CS228" Enrollment="110">
      <Title>Structured Probabilistic Models: Principles and Techniques</Title>
      <Description>Using probabilistic modeling languages to represent complex domains.</Description>
      <Instructors>
        <Professor>
          <First_Name>Daphne</First_Name>
          <Last_Name>Koller</Last_Name>    
        </Professor>
      </Instructors>
    </Course>

    <Course Number="CS229" Enrollment="320">
      <Title>Machine Learning</Title>
      <Description>A broad introduction to machine learning and statistical pattern recognition.</Description>
      <Instructors>
        <Professor>
          <First_Name>Andrew</First_Name>
          <Last_Name>Ng</Last_Name>    
        </Professor>
      </Instructors>
    </Course>

  </Department>

  <Department Code="EE">
  
    <Title>Electrical Engineering</Title>
    
    <Chair>
      <Professor>
        <First_Name>Mark</First_Name>
        <Middle_Initial>A.</Middle_Initial>
        <Last_Name>Horowitz</Last_Name>
      </Professor>    
    </Chair>
  
    <Course Number="EE108A">
      <Title>Digital Systems I</Title>
      <Description>Digital circuit, logic, and system design.</Description>
      <Instructors>
        <Professor>
          <First_Name>Subhasish</First_Name>
          <Last_Name>Mitra</Last_Name>
        </Professor>
      </Instructors>
    </Course>
    
    <Course Number="EE108B">
      <Title>Digital Systems II</Title>
      <Description>The design of processor-based digital systems.</Description>
      <Instructors>
        <Professor>
          <First_Name>William</First_Name>
          <Middle_Initial>J.</Middle_Initial>
          <Last_Name>Dally</Last_Name>
        </Professor>      
        <Professor>
          <First_Name>Oyekunle</First_Name>
          <Last_Name>Olukotun</Last_Name>
        </Professor>
      </Instructors>
      <Prerequisites>
        <Prereq>EE108A</Prereq>
        <Prereq>CS106B</Prereq>
      </Prerequisites>
    </Course>    
  
  </Department>

  <Department Code="LING">
  
    <Title>Linguistics</Title>
    
    <Chair>    
      <Professor>
        <First_Name>Beth</First_Name>
        <Last_Name>Levin</Last_Name>    
      </Professor>
    </Chair>

    <Course Number="LING180" Enrollment="60">
      <Title>From Languages to Information</Title>
      <Description>Natural language processing. Cross-listed as CS124.</Description>
      <Instructors>
        <Professor>
          <First_Name>Dan</First_Name>
          <Last_Name>Jurafsky</Last_Name>    
        </Professor>
      </Instructors>
      <Prerequisites>
        <Prereq>CS107</Prereq>
        <Prereq>CS109</Prereq>
      </Prerequisites>   
    </Course>
    
  </Department>
  
</Course_Catalog>