MLA

von Sankt Gallen, Heinrich. Passionstraktat; Prayers. 1475. https://collections.library.yale.edu/catalog/16576825.

APA, 6th edition

von Sankt Gallen, H. (1475). Passionstraktat; Prayers [Manuscripts, Medieval Germany 15th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/16576825.