Cita APA (7th ed.)

Swan, M., & Smith, B. (1991). Learner English: A teacher's guide to interference and other problems. Press Syndicate of the University of Cambridge.

Cita Chicago (17th ed.)

Swan, Michael, i Bernard Smith. Learner English: A Teacher's Guide to Interference and Other Problems. Cambridge [Cambridgeshire]: Press Syndicate of the University of Cambridge, 1991.

Cita MLA (9th ed.)

Swan, Michael, i Bernard Smith. Learner English: A Teacher's Guide to Interference and Other Problems. Press Syndicate of the University of Cambridge, 1991.