MLA

Petrus, Comestor, active 12th century. Historia scholastica. Vol. 1. [between 1450 and 1475]. https://collections.library.yale.edu/catalog/2013583.

APA, 6th edition

Petrus, Comestor, active 12th century. (["Vol. 1"])([between 1450 and 1475])[Historia scholastica]. https://collections.library.yale.edu/catalog/2013583.