Columbia subject headings:
Newark (N.J.)--Social conditions.
Skilled labor--New Jersey--Newark--History.
Working class--New Jersey--Newark--History.
Harvard subject headings:
Newark (N.J.)--Social conditions.
Skilled labor--New Jersey--Newark--History.
Working class--New Jersey--Newark--History.
Princeton subject headings:
Newark (N.J.)--Social conditions.
Skilled labor--New Jersey--Newark--History--19th century.
Working class--New Jersey--Newark--History--19th century.