MLA

Magnus, Charles, and lithographer. Brooklyn City Hall. Charles Magnus, 0AD. https://collections.library.yale.edu/catalog/2015963.

APA, 6th edition

Magnus, C., & lithographer. (0 C.E.). Brooklyn City Hall [Pictorial works, Lithographs, Letterheads]. Charles Magnus. https://collections.library.yale.edu/catalog/2015963.