World Tourism Organization. (1998). Guide for local authorities on developing sustainable tourism. World Tourism Organization.
Citazione stile Chigago Style (17a edizione)World Tourism Organization. Guide for Local Authorities on Developing Sustainable Tourism. Madrid, Spain: World Tourism Organization, 1998.
Citatione MLA (9a ed.)World Tourism Organization. Guide for Local Authorities on Developing Sustainable Tourism. World Tourism Organization, 1998.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.