Royal Geographical Society (Great Britain), Cater, E., & Lowman, G. (1994). Ecotourism: A sustainable option? Wiley.
Lua i Stíl Chicago (17ú heag.)Royal Geographical Society (Great Britain), Erlet Cater, agus Gwen Lowman. Ecotourism: A Sustainable Option? Chichester ; New York: Wiley, 1994.
Lua MLA (8ú heag.)Royal Geographical Society (Great Britain), et al. Ecotourism: A Sustainable Option? Wiley, 1994.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.