APA (7th ed.) Citation

United Nations Population Fund & Myers, N. (1991). Population, resources & the environment: The critical challenges. United Nations Population Fund.

Chicago Style (17th ed.) Citation

United Nations Population Fund and Norman Myers. Population, Resources & the Environment: The Critical Challenges. New York: United Nations Population Fund, 1991.

MLA (9th ed.) Citation

United Nations Population Fund and Norman Myers. Population, Resources & the Environment: The Critical Challenges. United Nations Population Fund, 1991.