MLA

H.H. Stratton (Firm). Troops disembarking. Folder 19. undated. https://collections.library.yale.edu/catalog/2017117.

APA, 6th edition

H.H. Stratton (Firm). (["Folder 19"])(undated)[Troops disembarking]. https://collections.library.yale.edu/catalog/2017117.