Columbia subject headings:
Petroleum industry and trade--Venezuela.
Venezuela--Economic conditions--1918-1958.
Venezuela--Politics and government--1935-
Harvard subject headings:
Petroleum industry and trade--Venezuela
Venezuela--Economic conditions--1918-
Venezuela--Politics and government--1935-
Princeton subject headings:
Petroleum industry and trade--Venezuela.
Venezuela--Economic conditions--1918-.
Venezuela--Politics and government--1935-