MLA

Rabanus Maurus, Archbishop of Mainz, 784?-856, Sirmond, Jacques, 1559-1651. Rabani archiepiscopi Mogvntini De praedestinatione Dei aduersus Gothescalcum epistolae III. Nunc primuíÛm in lucem editae cura & studio Iacobi Sirmondi .... 1647. https://collections.library.yale.edu/catalog/10156007.

APA, 6th edition

Rabanus Maurus, Archbishop of Mainz, 784?-856, & Sirmond, Jacques, 1559-1651. (1647)[Rabani archiepiscopi Mogvntini De praedestinatione Dei aduersus Gothescalcum epistolae III. Nunc primuíÛm in lucem editae cura & studio Iacobi Sirmondi ...]. https://collections.library.yale.edu/catalog/10156007.