<http://caligraph.org/ontology/Engine_introduced_in_the_1950s>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Engine> .
<http://caligraph.org/ontology/Engine_introduced_in_the_1950s>	<http://www.w3.org/2000/01/rdf-schema#label>	"Engine introduced in the 1950s" .
<http://caligraph.org/ontology/1950s_turbofan_engine>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Engine_introduced_in_the_1950s> .
<http://caligraph.org/ontology/1950s_turbojet_engine>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Engine_introduced_in_the_1950s> .
<http://caligraph.org/ontology/1950s_turboprop_engine>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Engine_introduced_in_the_1950s> .
<http://caligraph.org/ontology/1950s_aircraft_piston_engine>	<http://www.w3.org/2000/01/rdf-schema#subClassOf>	<http://caligraph.org/ontology/Engine_introduced_in_the_1950s> .
<http://caligraph.org/ontology/Engine_introduced_in_the_1950s>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://en.wikipedia.org/wiki/Category:Engines_introduced_in_the_1950s> .
<http://caligraph.org/ontology/Engine_introduced_in_the_1950s>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/2002/07/owl#Class> .