International Union for Conservation of Nature and Natural Resources & International Union for Conservation of Nature and Natural Resources. (1961). IUCN bulletin. International Union for Conservation of Nature and Natural Resources.
Chicago-Zitierstil (17. Ausg.)International Union for Conservation of Nature and Natural Resources und International Union for Conservation of Nature and Natural Resources. IUCN Bulletin. Morges, Switzerland: International Union for Conservation of Nature and Natural Resources, 1961.
MLA-Zitierstil (8. Ausg.)International Union for Conservation of Nature and Natural Resources und International Union for Conservation of Nature and Natural Resources. IUCN Bulletin. International Union for Conservation of Nature and Natural Resources, 1961.