MLA

Benedict, Saint, and Maurists Abbot of Monte Cassino. Regula Sanctissimi Patris Benedicti : Cum Declarationibus Congregationis Sancti Mauri : Iussu Et Authoritate Capituli Generalis Eiusdem Congregationis. s.n.], 1646. https://collections.library.yale.edu/catalog/10190183.

APA, 6th edition

Benedict, S., & Abbot of Monte Cassino, M. (1646). Regula sanctissimi patris Benedicti : cum declarationibus Congregationis Sancti Mauri : iussu et authoritate capituli generalis eiusdem congregationis. [Decorated initials, Devotional literature, Marginalia, woodcuts (AAT)]. s.n.], https://collections.library.yale.edu/catalog/10190183.