Columbia subject headings:
Communism--Argentina--History--20th century.
Labor unions--Argentina--History--20th century.
Syndicalism--Argentina--History--20th century.
Harvard subject headings:
Agricultural laborers--Argentina--Pampas--History.
Agricultural laborers--Labor unions--Argentina--Pampas--History.
Agriculture and state--Argentina--Pampas--History.
Pampas (Argentina)--Social conditions.
Princeton subject headings:
Agricultural laborers--Argentina--Pampas--History.
Agricultural laborers--Labor unions--Argentina--Pampas--History.
Agriculture and state--Argentina--Pampas--History.
Pampas (Argentina)--Social conditions.