MLA

Derby, George Horatio, 1823-1861. The Sacramento Valley from the American River to Butte Creek / surveyed & drawn by order of Genl. Riley, commandg. 10th Military Dept. by Lieut. Derby, Topl. Engrs., September & October, 1849.. BRBL_00608. 1850. https://collections.library.yale.edu/catalog/15818734.

APA, 6th edition

Derby, George Horatio, 1823-1861. (["BRBL_00608"])(1850)[The Sacramento Valley from the American River to Butte Creek / surveyed & drawn by order of Genl. Riley, commandg. 10th Military Dept. by Lieut. Derby, Topl. Engrs., September & October, 1849.]. https://collections.library.yale.edu/catalog/15818734.