Hudson, G. D. (1952). Encyclopedia Britannica world atlas: World distributions and world political geography, political-physical maps, geographical summaries, geographical comparisons, glossary of geographical terms, index to political-physical maps. Encyclopedia Britannica.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Hudson, George Donald. Encyclopedia Britannica World Atlas: World Distributions and World Political Geography, Political-physical Maps, Geographical Summaries, Geographical Comparisons, Glossary of Geographical Terms, Index to Political-physical Maps. Chicago: Encyclopedia Britannica, 1952.
Trích dẫn kiểu MLA (xuất bản lần thứ 9)Hudson, George Donald. Encyclopedia Britannica World Atlas: World Distributions and World Political Geography, Political-physical Maps, Geographical Summaries, Geographical Comparisons, Glossary of Geographical Terms, Index to Political-physical Maps. Encyclopedia Britannica, 1952.