Columbia subject headings:
Leaning Tower (Pisa, Italy)
Pisa (Italy)--Buildings, structures, etc.
Harvard subject headings:
Architecture--Italy--Pisa.
Bell towers--Italy--Pisa.
Leaning Tower (Pisa, Italy)
Pisa (Italy)--Buildings, structures, etc.
Princeton subject headings:
Architecture, Romanesque--Italy--Pisa.
Bell towers--Italy--Pisa.
Leaning Tower (Pisa, Italy)
Pisa (Italy)--Buildings, structures, etc.