MLA

Halgrin, John. Commentum in Cantica Canticorum. 0AD. https://collections.library.yale.edu/catalog/11007481.

APA, 6th edition

Halgrin, J. (0 C.E.). Commentum in Cantica Canticorum [Commentaries, Manuscripts, Medieval France 13th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/11007481.