Tietueen sitaatit

World Tourism Organization, International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme. Industry and Environment. Programme Activity Centre [väliaikainen hakumuoto], McNeely, J., Thorsell, J. W., & Ceballos-Lascuráin, H. (1992). Guidelines: Development of national parks and protected areas for tourism. World Tourism Organization : United Nations Environment Programme, Terrestrial Ecosystems Branch, Industry and Environment Programme Activity Centre.

World Tourism Organization, International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme. Industry and Environment. Programme Activity Centre [väliaikainen hakumuoto], Jeffrey McNeely, James W. Thorsell, ja Héctor Ceballos-Lascuráin. Guidelines: Development of National Parks and Protected Areas for Tourism. Madrid ; Paris: World Tourism Organization : United Nations Environment Programme, Terrestrial Ecosystems Branch, Industry and Environment Programme Activity Centre, 1992.

World Tourism Organization, et al. Guidelines: Development of National Parks and Protected Areas for Tourism. World Tourism Organization : United Nations Environment Programme, Terrestrial Ecosystems Branch, Industry and Environment Programme Activity Centre, 1992.

World Tourism Organization, International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme. Industry and Environment. Programme Activity Centre [väliaikainen hakumuoto], McNeely, J., Thorsell, J. W. & Ceballos-Lascuráin, H. 1992. Guidelines: Development of national parks and protected areas for tourism. Madrid ; Paris: World Tourism Organization : United Nations Environment Programme, Terrestrial Ecosystems Branch, Industry and Environment Programme Activity Centre.