Columbia subject headings:
Harvard subject headings:
Bibliographical services--Congresses.
Machine-readable bibliographic data--Congresses
Online bibliographic searching--Congresses
Reference services (Libraries)--Congresses.
Princeton subject headings:
Bibliographical services--Congresses.
Machine-readable bibliographic data--Congresses.
Online bibliographic searching--Congresses.
Reference services (Libraries)--Congresses.