Columbia subject headings:
Hours of labor--Illinois--Chicago.
Printers--Illinois--Chicago.
Printing industry--Vocational guidance--Illinois--Chicago.
Printing--Societies, etc.
Wages--Illinois--Chicago.
Harvard subject headings:
Princeton subject headings:
Hours of labor--Illinois--Chicago.
Printers--Illinois--Chicago.
Printing--Illinois--Chicago.
Printing--Societies, etc.
Wages--Illinois--Chicago.