Παραπομπή APA

Hill, J., & Gale, T. (2009). Ecotourism and environmental sustainability: Principles and practice. Farnham,: Ashgate.

Παραπομπή Chicago Style

Hill, Jennifer, and Tim Gale. Ecotourism and Environmental Sustainability: Principles and Practice. Farnham,: Ashgate, 2009.

Παραπομπή MLA

Hill, Jennifer, and Tim Gale. Ecotourism and Environmental Sustainability: Principles and Practice. Farnham,: Ashgate, 2009.

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