APA (7e ed.) Bronvermelding

Tolba, M. K., Lamb, R., & Allen, P. (1983). Earth matters: Environmental challenges for the l980s. United Nations Environment Programme.

Chicago (17e ed.) Bronvermelding

Tolba, Mostafa Kamal, Robert Lamb, en Patrick Allen. Earth Matters: Environmental Challenges for the L980s. Nairobi, Kenya: United Nations Environment Programme, 1983.

MLA (9e ed.) Bronvermelding

Tolba, Mostafa Kamal, et al. Earth Matters: Environmental Challenges for the L980s. United Nations Environment Programme, 1983.