Columbia subject headings:
Harvard subject headings:
Architecture--Italy--Modena.
City walls--Italy--Modena--Design and construction--History.
Fortification--Italy--Modena.
Masonry--Italy--Modena--History.
Modena (Italy)--Buildings, structures, etc.
Walls--Italy--Modena--Design and construction--History.
Princeton subject headings:
Architecture--Italy--Modena.
City walls--Italy--Modena--Design and construction--History.
Fortification--Italy--Modena.
Masonry--Italy--Modena--History.
Modena (Italy)--Buildings, structures, etc.
Walls--Italy--Modena--Design and construction--History.