APA (7th ed.) Citation

Lightbown, P. M., & Spada, N. (1999). How languages are learned (2a. ed.). Oxford University.

Chicago Style (17th ed.) Citation

Lightbown, Patsy M., and Nina Spada. How Languages Are Learned. 2a. ed. Oxford: Oxford University, 1999.

MLA (9th ed.) Citation

Lightbown, Patsy M., and Nina Spada. How Languages Are Learned. 2a. ed. Oxford University, 1999.