International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme, & World Wide Fund for Nature. (1991). Caring for the earth: A strategy for sustainable living. IUCN--the World Conservation Union, United Nations Environment Programme, World Wide Fund for Nature.
Παραπομπή σε μορφή Chicago (17η εκδ.)International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme, και World Wide Fund for Nature. Caring for the Earth: A Strategy for Sustainable Living. Gland: IUCN--the World Conservation Union, United Nations Environment Programme, World Wide Fund for Nature, 1991.
Παραπομπή σε μορφή MLA (9th εκδ.)International Union for Conservation of Nature and Natural Resources, et al. Caring for the Earth: A Strategy for Sustainable Living. IUCN--the World Conservation Union, United Nations Environment Programme, World Wide Fund for Nature, 1991.