Gaya APA
Azar, B, S. (1989).
Understanding and using English grammer / Betty Schrampfer Azar (2nd.ed).
:
Prentice Hall Regents.
Gaya MLA
Azar, Betty, Schrampfer.
"Understanding and using English grammer / Betty Schrampfer Azar".
2nd.ed
:
Prentice Hall Regents,
1989.
Referensi.