22nd engineers starting to build a bridge across the Rio Grande
MLA
22nd Engineers Starting to Build a Bridge across the Rio Grande. 0AD. https://collections.library.yale.edu/catalog/2017193.
APA, 6th edition
22nd engineers starting to build a bridge across the Rio Grande. (0 C.E.). [Photographic postcards, Photographic prints, Photographs]. https://collections.library.yale.edu/catalog/2017193.