MLA

of the Engineer Commissioner D.C, Office. Map of the Permanent System of Highways, District of Columbia / Prepared in the Office of the Engineer Commissioner D.C. s.n.], 1914. https://collections.library.yale.edu/catalog/15827555.

APA, 6th edition

of the Engineer Commissioner D.C, O. (1914). Map of the permanent system of highways, District of Columbia / prepared in the Office of the Engineer Commissioner D.C. [Maps]. s.n.], https://collections.library.yale.edu/catalog/15827555.