Columbia subject headings:
Working class--Mexico--Azcapotzalco (Mexico City)--History--20th century.
Harvard subject headings:
Azcapotzalco (Mexico City, Mexico)--Economic conditions.
Labor--Mexico--Azcapotzalco.
Princeton subject headings:
Azcapotzalco--Economic conditions.
Labor--Mexico--Azcapotzalco.