MLA

Higden, Ranulf, -1364. Polychronicon. [ca. 1325-1350]. https://collections.library.yale.edu/catalog/16371225.

APA, 6th edition

Higden, Ranulf, -1364. ([ca. 1325-1350])[Polychronicon]. https://collections.library.yale.edu/catalog/16371225.