Gaya APA
Schoenberg, I, E., Maurer, J. (2006).
Focus on grammar –an integrated skills approach (Ed. 2).
USA:
Pearson longman.
Gaya MLA
Schoenberg, Irene, E., Maurer, Jay.
"Focus on grammar –an integrated skills approach".
Ed. 2
USA:
Pearson longman,
2006.
Umum.