MLA

Broadside Press (Detroit, Michigan). Advertisement. Poems of Negro Revolt. Box 1 | Folder 30. circa 1970. https://collections.library.yale.edu/catalog/2107016.

APA, 6th edition

Broadside Press (Detroit, Michigan). (["Box 1 | Folder 30"])(circa 1970)[Advertisement. Poems of Negro Revolt]. https://collections.library.yale.edu/catalog/2107016.