MLA

Book of Hours, Use of Sarum. 0AD. https://collections.library.yale.edu/catalog/32343806.

APA, 6th edition

Book of hours, use of Sarum. (0 C.E.). [Prayers and devotions, Early works to 1800, Books of hours, Illuminated manuscripts Netherlands 15th century, Manuscripts, Medieval Netherlands 15th century, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/32343806.