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