This is the ValueSet that contains all the codes in Types of bibliographic artifacts (http://hl7.org/fhir/uv/order-catalog/ValueSet/bibliography-artifact-type) and Types of bibliographic artifacts (http://hl7.org/fhir/uv/order-catalog/ValueSet/bibliography-artifact-type). E.g. what you have to deal with if you get resources containing codes in either of them