Gaya APA

Peterson, P, W. (1997). Changing Times, Changing Tenses : With Explanation And Exercises Elementary, Intermediate Level . Jakarta: PT. Gramedia Pustaka Utama.

Gaya MLA

Peterson, Patricia, Wilcox. "Changing Times, Changing Tenses : With Explanation And Exercises Elementary, Intermediate Level". Jakarta: PT. Gramedia Pustaka Utama, 1997. Text.