Columbia subject headings:
Harvard subject headings:
Angels--Congresses.
Demonology--Congresses.
Gnosticism--Congresses
Neoplatonism--Congresses.
Plotinus
Porphyry, approximately 234-approximately 305.
Proclus, approximately 410-485.
Princeton subject headings:
Angels.
Demonology.
Neoplatonism.