Columbia subject headings:
Business information services.
Information services.
Harvard subject headings:
Business information services--Directories.
Business--Bibliography--Periodicals.
Business--Reference books--Bibliography--Periodicals.
Management--Bibliography--Periodicals
Management--Information services--Directories.
Reference books--Management--Bibliography--Periodicals.
Princeton subject headings:
Business information services--Directories.
Business--Bibliography.
Directories.
Information services--Directories.