Cite

Rand McNally official 1924 : auto trails map of Colorado.

MLA

McNally, Rand, and Company. Rand McNally Official 1924 : Auto Trails Map of Colorado. Rand McNally & Company, 0AD. https://collections.library.yale.edu/catalog/15818464.

APA, 6th edition

McNally, R., & C. (0 C.E.). Rand McNally official 1924 : auto trails map of Colorado. [Road maps]. Rand McNally & Company, https://collections.library.yale.edu/catalog/15818464.