MLA

Grammatical Treatise; Disticha Catonis. 0AD. https://collections.library.yale.edu/catalog/10622442.

APA, 6th edition

Grammatical treatise; Disticha Catonis. (0 C.E.). [Manuscripts, Medieval Italy 14th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/10622442.