MLA

Lewis, Jon, 1938-2009. Teatro Campesino II. Box 5, folder 35. 1966. https://collections.library.yale.edu/catalog/16728969.

APA, 6th edition

Lewis, Jon, 1938-2009. (["Box 5, folder 35"])(1966)[Teatro Campesino II]. https://collections.library.yale.edu/catalog/16728969.