Columbia subject headings:
Agricultural laborers--Labor unions--Spain--History.
Agriculture and state--Spain--History.
P.S.O.E. (Political party)--History.
Unión General de Trabajadores de España--History.
Harvard subject headings:
Agricultural laborers--Labor unions--Spain--History.
Agriculture and state--Spain--History.
P.S.O.E. (Political party)--History.
Unión General de Trabajadores de España--History.
Princeton subject headings:
Agricultural laborers--Labor unions--Spain--History.
Agriculture and state--Spain--History.
P.S.O.E. (Political party)--History.
Unión General de Trabajadores de España--History.