Cite

Unknown Photographer [Photograph of Charles Remond Douglass (1844-1920), seated with sword.] Later 19th Century Photograph.

MLA

Simpson, Randolph Linsly, 1927-1992. Unknown Photographer [Photograph of Charles Remond Douglass (1844-1920), seated with sword.] Later 19th Century Photograph.. Box 16, folder 756-a. circa 1864. https://collections.library.yale.edu/catalog/32312237.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 16, folder 756-a"])(circa 1864)[Unknown Photographer [Photograph of Charles Remond Douglass (1844-1920), seated with sword.] Later 19th Century Photograph.]. https://collections.library.yale.edu/catalog/32312237.