APA

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/ (Acc: 1015). Gland, Switzerland: IUCN--the World Conservation Union.

Chicago

International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme and World Wide Fund for Nature. 1991. Caring for the earth :a strategy for sustainable living/ (Acc: 1015). Gland, Switzerland: IUCN--the World Conservation Union.

Harvard

International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme and World Wide Fund for Nature. (1991). Caring for the earth :a strategy for sustainable living/ (Acc: 1015). Gland, Switzerland: IUCN--the World Conservation Union.

MLA

International Union for Conservation of Nature and Natural Resources, United Nations Environment Programme and World Wide Fund for Nature. Caring for the earth :a strategy for sustainable living/ (Acc: 1015). Gland, Switzerland: IUCN--the World Conservation Union. 1991.