MLA

Humphrys, F. Lengths of the Principal Rivers in the World. 1850. https://collections.library.yale.edu/catalog/2042180.

APA, 6th edition

Humphrys, F. (1850). Lengths of the principal rivers in the world [Atlases, Frontispieces (Illustrations), Illustrations, Lithographs, Maps, Maps in books, Planographic prints, Prints (Visual works)]. https://collections.library.yale.edu/catalog/2042180.