Columbia subject headings:
Guastalla (Italy)--Buildings, structures, etc.
Palaces--Italy--Guastalla.
Palazzo ducale (Guastalla, Italy)
Harvard subject headings:
Gonzaga family--Homes and haunts--Italy--Guastalla.
Guastalla (Italy)--Buildings, structures, etc.
Palazzo ducale (Guastalla, Italy)
Princeton subject headings:
Palaces--Italy--Guastalla.
Palazzo ducale (Guastalla, Italy).