Plato, Euthydemus, Protagoras, Gorgias, Meno, Εὐθύδημος 288:

καὶ ἡμῖν μὲν ἄπιστον ἐδόκει τὸ πρᾶγμα εἶναι· ὁ δ’ Εὐθύδημοσ, ἀπιστεῖσ, ἔφη, ὦ Σώκρατεσ;