Columbia subject headings:
Plato--Criticism and interpretation.
Plato--Language.
Plato. Epistles. 7th.
Harvard subject headings:
Plato--Criticism and interpretation.
Plato--Language.
Plato--Spurious and doubtful works.
Plato. Epistles 7.
Plato. Epistles 7th.
Political science--Early works to 1800
Utopias--Early works to 1800
Princeton subject headings:
Knowledge, Theory of.
Plato--Language.
Plato. Epistles. 7th
Semiotics--Philosophy.