Gaya APA
Abraham, P., Mackey, D. (1997).
Contact USA A Reading And Vocabulary Text (Edisi 3).
New jersey:
Prentice Hall.
Gaya MLA
Abraham, Paul., Mackey, Daphne.
"Contact USA A Reading And Vocabulary Text".
Edisi 3
New jersey:
Prentice Hall,
1997.
UMUM.