APA (7th ed.) Citation

National Geographic Society (U.S.), Chamberlin, W., & Grosvenor, G. H. (1947). The round earth on flat paper.: Map projections used by cartographers. [publisher not identified].

Chicago Style (17th ed.) Citation

National Geographic Society (U.S.), Wellman Chamberlin, and Gilbert Hovey Grosvenor. The Round Earth on Flat Paper.: Map Projections Used by Cartographers. Washington: [publisher not identified], 1947.

MLA (9th ed.) Citation

National Geographic Society (U.S.), et al. The Round Earth on Flat Paper.: Map Projections Used by Cartographers. [publisher not identified], 1947.