<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://en.wikipedia.org/wiki/Category:Books_about_opera> .
<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/2000/01/rdf-schema#label>	"Book about opera" .
<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Music_book> .
<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/2002/07/owl#Class> .
<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Non-fiction_book_about_theatre> .
<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/RestrictionHasValue_nonFictionSubject_Opera> .
<http://caligraph.org/ontology/Book_about_opera>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Work_about_opera> .