Columbia subject headings:
Gnosticism--Congresses.
Neoplatonism--Congresses.
Platonists--Congresses.
Harvard subject headings:
Gnosticism--Congresses
Neoplatonism--Congresses.
Platonists--Congresses.
Princeton subject headings:
Gnosticism--Congresses.
Neoplatonism--Congresses.
Platonists--Congresses.