Columbia subject headings:
Architecture--Italy--Bologna--Guidebooks.
Architecture--Italy--Bologna--History--19th century.
Architecture--Italy--Bologna--History--20th century.
Bologna (Italy)--Buildings, structures, etc.--Guidebooks.
Harvard subject headings:
Architecture, Modern--19th century--Italy--Bologna.
Architecture, Modern--20th century--Italy--Bologna.
Architecture--Italy--Bologna--Guidebooks.
Bologna (Italy)--Buildings, structures, etc.--Guidebooks.
Princeton subject headings:
Architecture, Modern--19th century--Italy--Bologna.
Architecture, Modern--20th century--Italy--Bologna.
Architecture--Italy--Bologna--Guidebooks.
Bologna (Italy)--Buildings, structures, etc.--Guidebooks.