Columbia subject headings:
Bibliography--Databases--Congresses.
Descriptive cataloging--Data processing--Congresses.
Machine-readable bibliographic data--Congresses.
Online library catalogs--Congresses.
Harvard subject headings:
Bibliography--Databases--Congresses.
Descriptive cataloging--Data processing--Congresses.
Machine-readable bibliographic data--Congresses.
Online library catalogs--Congresses.
Princeton subject headings: