This is the ValueSet that contains all the codes in x_ActRelationshipDocumentSPL (http://terminology.hl7.org/ValueSet/v3-xActRelationshipDocumentSPL) and x_ActRelationshipDocumentSPL (http://terminology.hl7.org/ValueSet/v3-xActRelationshipDocumentSPL). E.g. what you have to deal with if you get resources containing codes in either of them