Παραπομπή APA

United Nations Environment Programme., Pratt, L., World Tourism Organization., & UNWTO. (2012). Tourism in the Green Economy: Background Report. Madrid: World Tourism Organization.

Παραπομπή Chicago Style

United Nations Environment Programme., Lawrence Pratt, World Tourism Organization, and UNWTO. Tourism in the Green Economy: Background Report. Madrid: World Tourism Organization, 2012.

Παραπομπή MLA

United Nations Environment Programme., Lawrence Pratt, World Tourism Organization, and UNWTO. Tourism in the Green Economy: Background Report. Madrid: World Tourism Organization, 2012.

Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.