Columbia subject headings:
Parma (Italy)--Maps--Bibliography.
Parma (Italy)--Pictorial works--Bibliography.
Piacenza (Italy)--Maps--Bibliography.
Piacenza (Italy)--Pictorial works--Bibliography.
Harvard subject headings:
Parma (Italy)--Maps--Bibliography.
Parma (Italy)--Pictorial works--Bibliography.
Piacenza (Italy)--Maps--Bibliography.
Piacenza (Italy)--Pictorial works--Bibliography.
Princeton subject headings: