APA (7th ed.) Citation

O'Donnell, W. R., & Todd, L. (1991). Variety in contemporary English / W.R. O'Donnell and Loreto Todd (2nd ed.). Harper Collins.

Chicago Style (17th ed.) Citation

O'Donnell, W. R., and Loreto Todd. Variety in Contemporary English / W.R. O'Donnell and Loreto Todd. 2nd ed. London: Harper Collins, 1991.

MLA (9th ed.) Citation

O'Donnell, W. R., and Loreto Todd. Variety in Contemporary English / W.R. O'Donnell and Loreto Todd. 2nd ed. Harper Collins, 1991.

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