Columbia subject headings:
Harvard subject headings:
Electric apparatus and appliances--Periodicals
Electric industries--Periodicals
Electrical engineering--Periodicals
Electromechanical devices--Periodicals.
Industrial management--Periodicals
Maintenance--Periodicals.
Princeton subject headings:
Electrical engineering--Periodicals.
Industrial management--Periodicals.
Periodicals.
Telegraph--Periodicals.
Telephone--Periodicals.