Harmonicum enchiridion; with Gaudentius, Introductio harmonica
MLA
Nicomachus, of Gerasa. Harmonicum Enchiridion; with Gaudentius, Introductio Harmonica. 1585. https://collections.library.yale.edu/catalog/17470734.
APA, 6th edition
Nicomachus, of G. (1585). Harmonicum enchiridion; with Gaudentius, Introductio harmonica [Early works to 1800, Manuscripts, Medieval Italy 16th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/17470734.