APA (7 वां संस्करण) प्रशस्ति पत्र

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

शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र

ebrary, Inc, Jennifer Hill, और Tim Gale. Ecotourism and Environmental Sustainability: Principles and Practice. Farnham, England ; Burlington, VT: Ashgate, 2009.

एमएलए (9वां संस्करण) प्रशस्ति पत्र

ebrary, Inc, et al. Ecotourism and Environmental Sustainability: Principles and Practice. Ashgate, 2009.