http://opencaesar.io/sierra/requirement#refines
Property requirement:refines

oml:type

oml:UnreifiedRelation

rdf:type

	owl:AsymmetricProperty
	owl:IrreflexiveProperty
	owl:ObjectProperty

rdfs:domain

requirement:Requirement

rdfs:range

requirement:Requirement

rdfs:subPropertyOf

requirement:refines

owl:inverseOf

requirement:isRefinedBy