Columbia subject headings:
Harvard subject headings:
Kerr, Paul F. (Paul Francis), 1897-1981.
Mineralogy--Congresses
Mineralogy--United States--Congresses.
Mines and mineral resources--Congresses
Mines and mineral resources--United States--Congresses.
Princeton subject headings:
Kerr, Paul F. (Paul Francis), 1897-1981.
Mineralogy--Congresses.
Mineralogy--United States--Congresses.
Mines and mineral resources--Congresses.
Mines and mineral resources--United States--Congresses.