Columbia subject headings:
Apses (Architecture)--Italy.
Architecture, Medieval--Italy.
Church architecture--Italy.
Double cathedrals--Italy.
Liturgy and architecture--Italy.
Harvard subject headings:
Apses (Architecture)--Italy.
Architecture, Medieval--Italy.
Church architecture--Italy.
Double cathedrals--Italy.
Liturgy and architecture--Italy.
Princeton subject headings:
Apses (Architecture)--Italy.
Architecture, Medieval--Italy.
Church architecture--Italy.
Double cathedrals--Italy.
Liturgy and architecture--Italy.