Gaya APA

HELGESEN, M., ADAMS, K. (2001). Workplace English Office File (ed. 1, cet. 9). Inggris: Pearson Education Limited.

Gaya MLA

HELGESEN, Marc., ADAMS, Keith. "Workplace English Office File". ed. 1, cet. 9 Inggris: Pearson Education Limited, 2001. Text.