MLA

Photographic Postcards of Fort Ringgold, Texas. 0AD. https://collections.library.yale.edu/catalog/2013652.

APA, 6th edition

Photographic postcards of Fort Ringgold, Texas. (0 C.E.). [Pictorial works, Photographic prints, Postcards, Bird's-eye views]. https://collections.library.yale.edu/catalog/2013652.