MLA

Johnston, William Walker Whitehall, 1835-1886. Album Page 5. Verso, top: Portrait of William Walker Whitehall Johnston. Box 1, folder 3. circa 1859. https://collections.library.yale.edu/catalog/10944322.

APA, 6th edition

Johnston, William Walker Whitehall, 1835-1886. (["Box 1, folder 3"])(circa 1859)[Album Page 5. Verso, top: Portrait of William Walker Whitehall Johnston]. https://collections.library.yale.edu/catalog/10944322.