Cruz, R. G. (2009). Principles of travel and tourism: Introduction to tourism theory. Tourism Research Philippines.
Citazione stile Chigago Style (17a edizione)Cruz, Reil G. Principles of Travel and Tourism: Introduction to Tourism Theory. Quezon City: Tourism Research Philippines, 2009.
Citatione MLA (9a ed.)Cruz, Reil G. Principles of Travel and Tourism: Introduction to Tourism Theory. Tourism Research Philippines, 2009.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.