Swan, M., & Smith, B. (2001). Learner English: A teacher's guide to interference and other problems (2nd ed.). Cambridge University Press.

Swan, Michael, and Bernard Smith. Learner English: A Teacher's Guide to Interference and Other Problems. 2nd ed. Cambridge ; New York: Cambridge University Press, 2001.

Swan, Michael, and Bernard Smith. Learner English: A Teacher's Guide to Interference and Other Problems. 2nd ed. Cambridge University Press, 2001.