Gaya APA
Trappe, T., Tullis, G. (2006).
Intelligent Business : Coursebook (Upper Intermediate Business English) .
England:
Pearson Education.
Gaya MLA
Trappe, Tonya., Tullis, Graham.
"Intelligent Business : Coursebook (Upper Intermediate Business English)".
England:
Pearson Education,
2006.
Text.