Cite

[Photograph of soldiers behind sandbags and trenches]

MLA

Trenkle, Charles, Cpl. [Photograph of soldiers behind sandbags and trenches]. Folder 28. [1916 or 1917]. https://collections.library.yale.edu/catalog/2017147.

APA, 6th edition

Trenkle, Charles, Cpl. (["Folder 28"])([1916 or 1917])[[Photograph of soldiers behind sandbags and trenches]]. https://collections.library.yale.edu/catalog/2017147.