MLA

Ochoa Carrillo, Antonio, 1811-1883. Domínguez, Joaquín H. Autograph letter, signed: Hidalgo, to Antonio Ochoa. Box 1, folder 48. 1866 January 9. https://collections.library.yale.edu/catalog/32319964.

APA, 6th edition

Ochoa Carrillo, Antonio, 1811-1883. (["Box 1, folder 48"])(1866 January 9)[Domínguez, Joaquín H. Autograph letter, signed: Hidalgo, to Antonio Ochoa]. https://collections.library.yale.edu/catalog/32319964.