MLA

Stevens, Isaac Ingalls, 1818-1862. Preliminary sketch of the Northern Pacific Rail Road exploration and survey, by I. I. Stevens, Governor of Washington Territory.. BRBL_00620. [1855]. https://collections.library.yale.edu/catalog/15821558.

APA, 6th edition

Stevens, Isaac Ingalls, 1818-1862. (["BRBL_00620"])([1855])[Preliminary sketch of the Northern Pacific Rail Road exploration and survey, by I. I. Stevens, Governor of Washington Territory.]. https://collections.library.yale.edu/catalog/15821558.