Columbia subject headings:
Harvard subject headings:
Cadmium compounds--Congresses.
Copper compounds--Congresses.
Gold compounds--Congresses.
Mercury compounds--Congresses.
Silver compounds--Congresses.
Zinc compounds--Congresses.
Princeton subject headings:
Cadmium compounds--Congresses.
Copper compounds--Congresses.
Mercury compounds--Congresses.
Transition metal compounds--Congresses.
Zinc compounds--Congresses.