Columbia subject headings:
Harvard subject headings:
City walls--Italy--Padua--History--Exhibitions.
Gates--Italy--Padua--History--Exhibitions.
Padua (Italy)--Buildings, structures, etc.--Exhibitions.
Princeton subject headings:
City walls--Italy--Padua--History--Exhibitions.
Padua (Italy)--Buildings, structures, etc.--Exhibitions.
Padua (Italy)--History--Exhibitions.