MLA

Company, Sanborn Map. Georgetown, Sussex County, Delaware. Sanborn Map Company, 0AD. https://collections.library.yale.edu/catalog/16387376.

APA, 6th edition

Company, S. M. (0 C.E.). Georgetown, Sussex County, Delaware. [Cadastral maps, Fire insurance maps]. Sanborn Map Company, https://collections.library.yale.edu/catalog/16387376.