APA (7th ed.) Citation

Gray. (2008). Why Mars and Venus Collide. HarperElement.

Chicago Style (17th ed.) Citation

Gray. Why Mars and Venus Collide. London: HarperElement, 2008.

MLA (8th ed.) Citation

Gray. Why Mars and Venus Collide. HarperElement, 2008.

Warning: These citations may not always be 100% accurate.