MLA

William, of Nassington, -1354. Speculum vitae. Box. [ca. 1425]. https://collections.library.yale.edu/catalog/16037447.

APA, 6th edition

William, of Nassington, -1354. (["Box"])([ca. 1425])[Speculum vitae]. https://collections.library.yale.edu/catalog/16037447.