Thayer's sectional map of Colorado / compiled from the plats and records of the Surveyor General's Office, Denver, Colorado, and drawn by H. L. Thayer.
MLA
Thayer, H. L. Thayer's Sectional Map of Colorado / Compiled from the Plats and Records of the Surveyor General's Office, Denver, Colorado, and Drawn by H. L. Thayer. H.L. Thayer, 1871. https://collections.library.yale.edu/catalog/15818408.
APA, 6th edition
Thayer, H. L. (1871). Thayer's sectional map of Colorado / compiled from the plats and records of the Surveyor General's Office, Denver, Colorado, and drawn by H. L. Thayer. [Maps]. H.L. Thayer, https://collections.library.yale.edu/catalog/15818408.
