Columbia subject headings:
International agency libraries--Reference services--Congresses.
International agency publications--Congresses.
Harvard subject headings:
Bibliographical services--Congresses.
Government publications--Congresses.
International agency libraries--Reference services--Congresses.
International agency publications--Bibliography--Methodology--Congresses.
International agency publications--Congresses.
Reference services (Libraries)--Congresses.
Princeton subject headings: