MLA

Corpus Iuris Civilis. 9AD. https://collections.library.yale.edu/catalog/2043576.

APA, 6th edition

Corpus iuris civilis. (9 C.E.). [Manuscripts, Medieval Italy 9th century, Medieval and Renaissance Manuscript Fragments in Beinecke Library, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/2043576.