Columbia subject headings:
Industrial relations--Spain--Periodicals.
Labor supply--Spain--Periodicals.
Labor unions--Spain--Periodicals.
Working class--Spain--Periodicals.
Harvard subject headings:
Princeton subject headings:
Industrial relations--Spain--Periodicals.
Labor supply--Spain--Periodicals.
Labor unions--Spain--Periodicals.
Periodicals.
Working class--Spain--Periodicals.