Columbia subject headings:
Electrical engineering.
Factory management.
Industrial efficiency--To 1930.
Telegraph.
Telephone.
Harvard subject headings:
Electrical engineering
Factory management---1930.
Industrial efficiency--Before 1930.
Telegragh.
Telephone
Princeton subject headings:
Electrical engineering--Periodicals.
Industrial management--Periodicals.
Periodicals.
Telegraph--Periodicals.
Telephone--Periodicals.