Columbia subject headings:
Contracts--Congresses.
Copyright, International--Congresses.
Copyright--Artistic performance--Congresses.
Copyright--Congresses.
Copyright--Societies, etc.--Congresses.
Labor unions--Artists--Congresses.
Harvard subject headings:
Artists--Labor unions--Congresses.
Contracts--Congresses.
Copyright, International--Congresses.
Copyright--Artistic performance--Congresses.
Copyright--Congresses.
Copyright--Societies, etc.--Congresses.
Princeton subject headings: