Columbia subject headings:
Basilica di San Pietro in Vaticano.
Christian antiquities--Vatican City.
Christian art and symbolism--Vatican City.
Peter, the Apostle, Saint--Art.
Vatican City--Antiquities.
Harvard subject headings:
Basilica di San Pietro in Vaticano.
Peter, the Apostle, Saint--Tomb.
Princeton subject headings:
Basilica di San Pietro in Vaticano.
Peter, the Apostle, Saint--Relics.
Vatican City--Buildings, structures, etc.