Citazione Stile APA (7a Edizione)

(1991). World directory of documentation resources and systems for the travel and tourism sector. WTO.

Citazione stile Chigago Style (17a edizione)

World Directory of Documentation Resources and Systems for the Travel and Tourism Sector. Madrid: WTO, 1991.

Citatione MLA (9a ed.)

World Directory of Documentation Resources and Systems for the Travel and Tourism Sector. WTO, 1991.