Gaya APA

Nababan, P., Sutomo, H, S. (1989). An Intermediate English course for student : pilots / P.W.J. Nababan dkk. . Jakarta: Kesaint Blanc.

Gaya MLA

Nababan, P.W.J.., Sutomo, Herry6aWidharto,, S.. "An Intermediate English course for student : pilots / P.W.J. Nababan dkk.". Jakarta: Kesaint Blanc, 1989. Textbook.