Gaya APA

Azar, B, S., FREESE, R, H. (1989). Understanding and using english grammar (2 nd.Ed). New Jersey: Pretentice Hall Regents.

Gaya MLA

Azar, Betty, Schrampfer., FREESE, Ros, Herion. "Understanding and using english grammar". 2 nd.Ed New Jersey: Pretentice Hall Regents, 1989. Text.