Columbia subject headings:
Apartment houses--Europe--History--20th century.
Apartment houses--Italy--Emilia-Romagna--History--20th century.
City planning--Europe--History--20th century.
City planning--Italy--Emilia-Romagna--History--20th century.
Working class--Dwellings--Europe--History--20th century.
Working class--Dwellings--Italy--Emilia-Romagna--History--20th century.
Harvard subject headings:
Aparment houses--Italy--Emilia-Romagna--History--20th century.
Apartment houses--Europe--History--20th century.
City planning--Europe--History--20th century
City planning--Italy--Emilia-Romagna--History--20th century.
Working class--Dwellings--Europe--History--20th century.
Working class--Dwellings--Italy--Emilia-Romagna--History--20th century.
Princeton subject headings: