MLA

of the Census, United States. Bureau. Arizona : Minor Civil Divisions / Department of Commerce, Bureau of the Census, 1930. Bureau of the Census, 1934. https://collections.library.yale.edu/catalog/15818609.

APA, 6th edition

of the Census, U. S. B. (1934). Arizona : minor civil divisions / Department of Commerce, Bureau of the Census, 1930. [Maps]. Bureau of the Census, https://collections.library.yale.edu/catalog/15818609.