MLA

Berengaudus, active approximately 859. Apocalypse commentary. [between 1000 and 1100].. https://collections.library.yale.edu/catalog/10621975.

APA, 6th edition

Berengaudus, active approximately 859. ([between 1000 and 1100].)[Apocalypse commentary]. https://collections.library.yale.edu/catalog/10621975.