World Tourism Organization. (1981). Organization and operation of the statistics service within the National Tourism Administration: Basic guidelines. The Organization.
Chicago-viite (17. p.)World Tourism Organization. Organization and Operation of the Statistics Service Within the National Tourism Administration: Basic Guidelines. Madrid: The Organization, 1981.
MLA-viite (9. p.)World Tourism Organization. Organization and Operation of the Statistics Service Within the National Tourism Administration: Basic Guidelines. The Organization, 1981.
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