APA (7th ed.) Citation

Ward, P. D. (2007). Under a green sky: Global warming, the mass extinctions of the past, and what they mean for our future. Smithsonian Books/Collins.

Chicago Style (17th ed.) Citation

Ward, Peter Douglas. Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Mean for Our Future. New York: Smithsonian Books/Collins, 2007.

MLA (8th ed.) Citation

Ward, Peter Douglas. Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Mean for Our Future. Smithsonian Books/Collins, 2007.