A minimum working example for testing bibliography

sample.bib

@article{Cal2000,
author = {Calude, Andreea S.},
title = {The journey of the four colour theorem through time},
journal = {The New Zealand Mathematics Magazine},
year = {2001},
volume = {38},
number = {3},
pages = {27-35},
}

@book{ivanhoe2000confucian,
  title={Confucian Moral Self Cultivation},
  author={Ivanhoe, P.J.},
  isbn={9780872205086},
  lccn={99052082},
  url={http://www.google.com.hk/books?id=W7XRfHzoUt8C},
  year={2000},
  publisher={Hackett Pub.}
}

@book{lindberg2010beginnings,
  title={The Beginnings of Western Science: The European Scientific Tradition in Philosophical, Religious, and Institutional Context, Prehistory to A.D. 1450, Second Edition},
  pages="51",
  author={Lindberg, D.C.},
  year={2010},
  publisher={University of Chicago Press}
}

testing.tex

\documentclass[11pt,a4paper,english]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{lmodern} % Default Computer Modern Fonts look ugly

\begin{document}
\nocite{*}
\bibliographystyle{alpha}
\bibliography{sample}
\end{document}