Gaya APA

Keller, D, P., Thrush, E, A. (1987). Interactions 1 A Speaking Activities Book . United States of America: MCGRAW-HILL BOOK COMPANY.

Gaya MLA

Keller, Deborah, Poole., Thrush, Emily, Austin. "Interactions 1 A Speaking Activities Book". United States of America: MCGRAW-HILL BOOK COMPANY, 1987. Text.