MLA

Preuss, Charles, 1803-1854. Topographical map of the road from Missouri to Oregon : commencing at the mouth of the Kansas in the Missouri River and ending at the mouth of the Wallah Wallah in the Columbia / from the field notes and journal of Capt. J.C. Frémont, and from sketches a. BRBL_00533. 1846]. https://collections.library.yale.edu/catalog/15812924.

APA, 6th edition

Preuss, Charles, 1803-1854. (["BRBL_00533"])(1846])[Topographical map of the road from Missouri to Oregon : commencing at the mouth of the Kansas in the Missouri River and ending at the mouth of the Wallah Wallah in the Columbia / from the field notes and journal of Capt. J.C. Frémont, and from sketches a]. https://collections.library.yale.edu/catalog/15812924.