Columbia subject headings:
Harvard subject headings:
Air conditioning--Congresses
Air conditioning--Congresses.
Commercial buildings--Power supply--Congresses.
Electric heating--Congresses.
Electric power-plants--Congresses.
Factories--Power supply--Congresses.
Princeton subject headings:
Air conditioning--Congresses.
Commercial buildings--Power supply--Congresses.
Electric heating--Congresses.
Electric power-plants--Congresses.
Factories--Power supply--Congresses.