Columbia subject headings:
P.S.O.E. (Political party)--History.
Socialism--Spain--History.
Spain--Politics and government--1875-1885.
Spain--Politics and government--1886-1931.
Spain--Politics and government--1931-1939.
Harvard subject headings:
P.S.O.E. (Political party)--History.
Socialism--Spain
Socialism--Spain--History
Spain--Politics and government--1875-1885.
Spain--Politics and government--1886-1931.
Spain--Politics and government--1931-1939.
Princeton subject headings:
P.S.O.E. (Political party)--History.
Socialism--Spain--History.
Spain--Politics and government--1875-1885.
Spain--Politics and government--1886-1931.
Spain--Politics and government--1931-1939.