MLA

Sartre, Jean-Paul, 1905-1980. Interview 20. Box 1, folder 19. 1972 Jan 7. https://collections.library.yale.edu/catalog/16538173.

APA, 6th edition

Sartre, Jean-Paul, 1905-1980. (["Box 1, folder 19"])(1972 Jan 7)[Interview 20]. https://collections.library.yale.edu/catalog/16538173.