[Map of Hungary showing nationalities] / geographical data compiled by B. C. Wallis.
MLA
[Map of Hungary Showing Nationalities] / Geographical Data Compiled by B. C. Wallis. American Geographical Society of New York, 1918. https://collections.library.yale.edu/catalog/15238054.
APA, 6th edition
[Map of Hungary showing nationalities] / geographical data compiled by B. C. Wallis. (1918). [Maps]. American Geographical Society of New York, https://collections.library.yale.edu/catalog/15238054.