Gaya APA

Gass, S, M., Selinker, L. (2008). Second language acquisition : an introductory course (3rd ed). New York: Routledge.

Gaya MLA

Gass, Susan, M.., Selinker, Larry. "Second language acquisition : an introductory course". 3rd ed New York: Routledge, 2008. Text.