Tolba, M. K., Lamb, R., & Allen, P. (1983). Earth matters: Environmental challenges for the l980s. United Nations Environment Programme.
Lua i Stíl Chicago (17ú heag.)Tolba, Mostafa Kamal, Robert Lamb, agus Patrick Allen. Earth Matters: Environmental Challenges for the L980s. Nairobi, Kenya: United Nations Environment Programme, 1983.
Lua MLA (9ú heag.)Tolba, Mostafa Kamal, et al. Earth Matters: Environmental Challenges for the L980s. United Nations Environment Programme, 1983.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.