Cite

Nell's topographical map of the state of Colorado / Louis Nell.

MLA

Nell, Louis. Nell's Topographical Map of the State of Colorado / Louis Nell. E. Besly & Co., 1892. https://collections.library.yale.edu/catalog/15818417.

APA, 6th edition

Nell, L. (1892). Nell's topographical map of the state of Colorado / Louis Nell. [Maps]. E. Besly & Co., https://collections.library.yale.edu/catalog/15818417.