Cite

Whitney's map of Portland and environs / compiled ... by the Real Estate Title and Trust Co. ; compliments of L.E. Thompson & Co., real estate brokers ; Everts & Howell, engravers.

MLA

Whitney, W. H. Whitney's Map of Portland and Environs / Compiled ... by the Real Estate Title and Trust Co. ; Compliments of L.E. Thompson & Co., Real Estate Brokers ; Everts & Howell, Engravers. W.H. Whitney?, 1889. https://collections.library.yale.edu/catalog/15821590.

APA, 6th edition

Whitney, W. H. (1889). Whitney's map of Portland and environs / compiled ... by the Real Estate Title and Trust Co. ; compliments of L.E. Thompson & Co., real estate brokers ; Everts & Howell, engravers. [Maps]. W.H. Whitney?, https://collections.library.yale.edu/catalog/15821590.