ebrary, Inc, Hill, J., & Gale, T. (2009). Ecotourism and environmental sustainability: Principles and practice. Ashgate.
Chicago Style (17. basım) Atıfebrary, Inc, Jennifer Hill, ve Tim Gale. Ecotourism and Environmental Sustainability: Principles and Practice. Farnham, England ; Burlington, VT: Ashgate, 2009.
MLA (9th ed.) Atıfebrary, Inc, et al. Ecotourism and Environmental Sustainability: Principles and Practice. Ashgate, 2009.
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