Gaya APA

Schoenberg, I, E., Maurer, J. (2002). Focus on grammar : an introduction course for reference and practice . New York: Longman Addison Wesley.

Gaya MLA

Schoenberg, Irene, E.., Maurer, Jay. "Focus on grammar : an introduction course for reference and practice". New York: Longman Addison Wesley, 2002. Text.