MLA

Dunbar, Rudolph, 1899-1988. Memorial service for Martin Luther King. Box 2, folder 45. 1968. https://collections.library.yale.edu/catalog/17398755.

APA, 6th edition

Dunbar, Rudolph, 1899-1988. (["Box 2, folder 45"])(1968)[Memorial service for Martin Luther King]. https://collections.library.yale.edu/catalog/17398755.