Isagoge artis musicae
Bacchius Geron
Bacchius Geron. Musici Scriptores Graeci. Jan, Karl von, editor. Leipzig: Teubner, 1895.
Τὸ οὖν ἁρμονικόν πῶς μελῳδεῖται; — Ἐπὶ μὲν τὸ δξὺ κατὰ δίεσιν καὶ δίεσιν καὶ δίτονον, ἐπὶ δὲ τὸ βαρὑ κατὰ τοὐναντίον. (p. 7)