Παραπομπή σε μορφή APA (7η εκδ.)

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

Παραπομπή σε μορφή Chicago (17η εκδ.)

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

Παραπομπή σε μορφή MLA (9th εκδ.)

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