Middleton, J., & Waltham, T. (1992). The underground atlas: A gazetteer of the world's cave regions. Promotional Reprint Company.
Chicago Style (17. basım) AtıfMiddleton, John, ve Tony Waltham. The Underground Atlas: A Gazetteer of the World's Cave Regions. Leiscester, Eng: Promotional Reprint Company, 1992.
MLA (9th ed.) AtıfMiddleton, John, ve Tony Waltham. The Underground Atlas: A Gazetteer of the World's Cave Regions. Promotional Reprint Company, 1992.
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