MLA

Ochoa Carrillo, Antonio, 1811-1883. Juárez, Benito. Autograph letter, signed: Chihuahua, to Antonio Ochoa Carrillo. Box 1, folder 59. 1866 August 21. https://collections.library.yale.edu/catalog/32320086.

APA, 6th edition

Ochoa Carrillo, Antonio, 1811-1883. (["Box 1, folder 59"])(1866 August 21)[Juárez, Benito. Autograph letter, signed: Chihuahua, to Antonio Ochoa Carrillo]. https://collections.library.yale.edu/catalog/32320086.