MLA

Johnston, William Walker Whitehall, 1835-1886. Album Page 35. Verso: Portrait of an enlisted man in the 1st West India Regiment. Box 1, folder 33. circa 1860. https://collections.library.yale.edu/catalog/33086928.

APA, 6th edition

Johnston, William Walker Whitehall, 1835-1886. (["Box 1, folder 33"])(circa 1860)[Album Page 35. Verso: Portrait of an enlisted man in the 1st West India Regiment]. https://collections.library.yale.edu/catalog/33086928.