Gaya APA
Harahap, H, A., Adnan, A. (1986).
a Practical english grammar/A.J.Thomson, A.V.Martinet (4th.Ed.).
Jena ::
Oxford University Press.
Gaya MLA
Harahap, H., Adnan., Adnan, Asmadi.
"a Practical english grammar/A.J.Thomson, A.V.Martinet".
4th.Ed.
Jena ::
Oxford University Press,
1986.
.