At the Lighthouse [Hermosa Beach, CA?]
MLA
Longstreet, Stephen, 1907-2002. At the Lighthouse [Hermosa Beach, CA?]. Box 4, folder 19. undated. https://collections.library.yale.edu/catalog/16723270.
APA, 6th edition
Longstreet, Stephen, 1907-2002. (["Box 4, folder 19"])(undated)[At the Lighthouse [Hermosa Beach, CA?]]. https://collections.library.yale.edu/catalog/16723270.