MLA

Illuminated Leaf from a Gradual (Beinecke MS 42). 0AD. https://collections.library.yale.edu/catalog/15763577.

APA, 6th edition

Illuminated leaf from a gradual (Beinecke MS 42). (0 C.E.). [Manuscripts, Medieval Italy 15th century, Manuscripts, Renaissance Italy 15th century, Medieval and Renaissance Manuscript Fragments in Beinecke Library, Medieval and Renaissance Manuscripts in Beinecke Library]. https://collections.library.yale.edu/catalog/15763577.