Columbia subject headings:
Labor unions--Argentina--History--20th century.
Social security--Argentina--History--20th century.
Strikes and lockouts--Argentina--History--20th century.
Working class--Argentina--History--20th century.
Harvard subject headings:
Labor unions--Argentina--History--20th century
Social security--Argentina--History--20th century.
Strikes and lockouts--Argentina--History--20th century.
Working class--Argentina--History--20th century.
Princeton subject headings:
Social security--Argentina.