APA
International Union for Conservation of Nature and Natural Resources, . (1971). Occasional paper / International Union for Conservation of Nature and Natural Resources, IUCN. Morges: IUCN.
Chicago
International Union for Conservation of Nature and Natural Resources, . 1971. Occasional paper / International Union for Conservation of Nature and Natural Resources, IUCN. Morges: IUCN.
Harvard
International Union for Conservation of Nature and Natural Resources, . (1971). Occasional paper / International Union for Conservation of Nature and Natural Resources, IUCN. Morges: IUCN.
MLA
International Union for Conservation of Nature and Natural Resources, . Occasional paper / International Union for Conservation of Nature and Natural Resources, IUCN. Morges: IUCN. 1971.