Columbia subject headings:
Industrial equipment--Maintenance and repair--Information services.
Machinery--Maintenance and repair--Information services.
Plant maintenance--Information services.
Harvard subject headings:
Machinery--Maintenance and repair--Information services.
Plant maintenance--Information services.
Princeton subject headings:
Industrial equipment--Maintenance and repair--Bibliography.
Industrial equipment--Maintenance and repair--Information services--Directories.
Plant maintenance--Bibliography.
Plant maintenance--Information services--Directories.