MLA

Nusbaumer, George L. (George Lewis). Map of the Black & Rose tracts, Alameda Co., Cal. / Geo. L. Nusbaumer, county surveyor.. BRBL_00612. 1887. https://collections.library.yale.edu/catalog/15821437.

APA, 6th edition

Nusbaumer, George L. (George Lewis). (["BRBL_00612"])(1887)[Map of the Black & Rose tracts, Alameda Co., Cal. / Geo. L. Nusbaumer, county surveyor.]. https://collections.library.yale.edu/catalog/15821437.