gistfile1.txt

select ?person ?authship ?publication
where
{
  ?person rdf:type foaf:Person .
  ?person core:authorInAuthorship ?authship .
  ?authip core:linkedInformationResource ?publication .
  
  ?publication rdf:type ?pub_type .
  optional { ?pub_type rdf:type core:Journal }
  filter(!bound(?publication))
}