Cita APA (7a ed.)

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

Cita Chicago Style (17a ed.)

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

Cita MLA (8a ed.)

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