龚勋 & 董明. (2009). 世界自然奇观: Natural wonders of the world. 云南教育出版社.
Chicago Style (17th ed.) Citation龚勋 and 董明. 世界自然奇观: Natural Wonders of the World. 云南教育出版社, 2009.
MLA citiranje龚勋 and 董明. 世界自然奇观: Natural Wonders of the World. 云南教育出版社, 2009.
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