APA (7th ed.) Citation

Malthus, T. R., & Gilbert, G. (2008). An essay on the principle of population. Oxford University Press.

Chicago Style (17th ed.) Citation

Malthus, T. R., and Geoffrey Gilbert. An Essay on the Principle of Population. Oxford ; New York: Oxford University Press, 2008.

MLA (8th ed.) Citation

Malthus, T. R., and Geoffrey Gilbert. An Essay on the Principle of Population. Oxford University Press, 2008.