Summa de virtutibus
MLA
Guilelmus Peraldus, ca. 1190-1271. Summa de virtutibus. [between 1200 and 1300]. https://collections.library.yale.edu/catalog/10563086.
APA, 6th edition
Guilelmus Peraldus, ca. 1190-1271. ([between 1200 and 1300])[Summa de virtutibus]. https://collections.library.yale.edu/catalog/10563086.