Παραπομπή APA

World Tourism Organization. (1996). WTO -ETAG joint seminar: Tourism and environmental protection, Heidelberg, Germany, 16 - 18 May 1996. Madrid, Spain: World Tourism Organization.

Παραπομπή Chicago Style

World Tourism Organization. WTO -ETAG Joint Seminar: Tourism and Environmental Protection, Heidelberg, Germany, 16 - 18 May 1996. Madrid, Spain: World Tourism Organization, 1996.

Παραπομπή MLA

World Tourism Organization. WTO -ETAG Joint Seminar: Tourism and Environmental Protection, Heidelberg, Germany, 16 - 18 May 1996. Madrid, Spain: World Tourism Organization, 1996.

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