Columbia subject headings:
Harvard subject headings:
Architecture--Italy--Rome--Guidebooks.
Catholic Church--Italy--Rome--Guidebooks.
Christian antiquities--Italy--Rome--Guidebooks.
Rome (Italy)--Buildings, structures, etc.--Guidebooks.
Rome (Italy)--Guidebooks.
Vatican City--Buildings, structures, etc.--Guidebooks.
Vatican City--Guidebooks.
Princeton subject headings:
Catholic Church--Italy--Rome--Guidebooks.
Christian antiquities--Italy--Rome--Guidebooks.
Rome (Italy)--Buildings, structures, etc.--Guidebooks.
Vatican City--Buildings, structures, etc.--Guidebooks.