Sharpe, P. J. (2012). Barron's Toefl iBT: Internet based test. Tp. Hồ Chí Minh: Tổng hợp Tp. Hồ Chí Minh.
Παραπομπή Chicago StyleSharpe, Pamela J. Barron's Toefl IBT: Internet Based Test. Tp. Hồ Chí Minh: Tổng hợp Tp. Hồ Chí Minh, 2012.
Παραπομπή MLASharpe, Pamela J. Barron's Toefl IBT: Internet Based Test. Tp. Hồ Chí Minh: Tổng hợp Tp. Hồ Chí Minh, 2012.
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