Columbia subject headings:
Duomo (Pisa, Italy)--Organs.
Organ (Musical instrument)--Italy--Pisa.
Harvard subject headings:
Duomo (Pisa, Italy)--Organ.
Organ (Musical instrument)--Italy--Pisa.
Princeton subject headings:
Duomo (Pisa, Italy)--Organs.
Organ (Musical instrument)--Italy--Pisa.