APA (7th ed.) Citation

Upton, C., & Widdowson, J. D. A. (1996). An atlas of English dialects. Oxford University Press.

Chicago Style (17th ed.) Citation

Upton, Clive, and J. D. A. Widdowson. An Atlas of English Dialects. New York: Oxford University Press, 1996.

MLA (9th ed.) Citation

Upton, Clive, and J. D. A. Widdowson. An Atlas of English Dialects. Oxford University Press, 1996.