MLA

Anastasius, Sinaita, Saint, active 640-700. Passages on asceticism. [between 1500 and 1600]. https://collections.library.yale.edu/catalog/11706792.

APA, 6th edition

Anastasius, Sinaita, Saint, active 640-700. ([between 1500 and 1600])[Passages on asceticism]. https://collections.library.yale.edu/catalog/11706792.