Fragmenta varia
Theophrastus
Theophrastus. Theophrasti Eresii Opera, Quae Supersunt, Omnia. Wimmer, Friedrich, editor. Paris: A.F. Didot, 1866.
Fr. 63b
Θ. δὲ καὶ ταύτην τὴν ἀποφατικὴν ἐνδεχομένην ὁμοίως ταῖς ἄλλαις ἀποφατικαῖς φησὶν ἀντιστρέφειν. (Alex. in Arist. Anal. pr. p. 150 Bk.)