World Tourism Organization. (1981). Organization and operation of the statistics service within the National Tourism Administration: Basic guidelines. The Organization.
Lua i Stíl Chicago (17ú heag.)World Tourism Organization. Organization and Operation of the Statistics Service Within the National Tourism Administration: Basic Guidelines. Madrid: The Organization, 1981.
Lua MLA (9ú heag.)World Tourism Organization. Organization and Operation of the Statistics Service Within the National Tourism Administration: Basic Guidelines. The Organization, 1981.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.