MLA

Cicero, Marcus Tullius. Epistolae Ad Familiares. 0AD. https://collections.library.yale.edu/catalog/2052749.

APA, 6th edition

Cicero, M. T. (0 C.E.). Epistolae ad familiares [Manuscripts, Medieval Germany 11th century, Medieval and Renaissance Manuscript Fragments in Beinecke Library, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/2052749.