Columbia subject headings:
Art, European--Italy--Orvieto.
Duomo di Orvieto (Orvieto, Italy)--History.
Foreign workers--Italy--Orvieto--History.
Opera del Duomo di Orvieto--History--Sources--Catalogs.
Opera del Duomo di Orvieto--History.
Harvard subject headings:
Church architecture--Italy--Orvieto--History--Sources.
Church architecture--Italy--Orvieto--History.
Church decoration and ornament--Italy--Orvieto--History--Sources.
Church decoration and ornament--Italy--Orvieto--History.
Duomo di Orvieto (Orvieto, Italy)--History--Sources.
Duomo di Orvieto (Orvieto, Italy)--History.
Princeton subject headings:
Art, European--Italy--Orvieto.
Duomo di Orvieto (Orvieto, Italy)--History.
Foreign workers--Italy--Orvieto--History.
Opera del Duomo di Orvieto--History--Sources--Catalogs.
Opera del Duomo di Orvieto--History.