MLA

Ochoa Carrillo, Antonio, 1811-1883. Ochoa Carrillo, Antonio. Autograph letter, signed: Guadalupe y Calvo, to Ramón Corona. Box 1, folder 50. 1866 April 20. https://collections.library.yale.edu/catalog/32319982.

APA, 6th edition

Ochoa Carrillo, Antonio, 1811-1883. (["Box 1, folder 50"])(1866 April 20)[Ochoa Carrillo, Antonio. Autograph letter, signed: Guadalupe y Calvo, to Ramón Corona]. https://collections.library.yale.edu/catalog/32319982.