Columbia subject headings:
Plato--Congresses.
Plato. Symposium--Congresses.
Harvard subject headings:
Plato--Congresses.
Plato. Symposium--Congresses.
Symposium Platonicum (10 : 2013 : Pise, Italie)
Princeton subject headings:
Plato--Congresses.
Plato. Symposium--Congresses.