MLA

Colorado Summer. [Atchison, Topeka, and Santa Fe Railway Co.?], Press of Henry O. Shepard Co, 1922. https://collections.library.yale.edu/catalog/2042662.

APA, 6th edition

Colorado summer. (1922). [Advertisements, Halftones, Illustrations, Maps, Pamphlets]. [Atchison, Topeka, and Santa Fe Railway Co.?], Press of Henry O. Shepard Co. https://collections.library.yale.edu/catalog/2042662.