MLA

Unidentified Philosophical Commentary (Fragment). 13AD. https://collections.library.yale.edu/catalog/10543763.

APA, 6th edition

Unidentified philosophical commentary (fragment). (13 C.E.). [Manuscripts, Medieval England 13th century, Medieval and Renaissance Manuscript Fragments in Beinecke Library, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/10543763.