MLA

Quesvel, Petrus. Directorium Iuris, Etc. 0AD. https://collections.library.yale.edu/catalog/2052957.

APA, 6th edition

Quesvel, P. (0 C.E.). Directorium iuris, etc [Manuscripts, Medieval France 14th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/2052957.