Columbia subject headings:
Harvard subject headings:
BRS (Information retrieval system)
Bibliographic Retrieval Services, Inc.
DIALOG (Information retrieval system)
Information retrieval.
ORBIT (Information retrieval system)
Online bibliographic searching.
Princeton subject headings:
Bibliographic Retrieval Services, Inc.
DIALOG (Information retrieval system)
Information retrieval.
ORBIT (Information retrieval system)
Online bibliographic searching.