ETS. (2016). OFFICIAL TOEFL iBT TESTS VOLUME 2 (WITH CD) (2ND ED.). MC GRAW HILL.
Chicago Style aipamenaETS. OFFICIAL TOEFL IBT TESTS VOLUME 2 (WITH CD). 2ND ED. NEW DELHI: MC GRAW HILL, 2016.
MLA aipamenaETS. OFFICIAL TOEFL IBT TESTS VOLUME 2 (WITH CD). 2ND ED. MC GRAW HILL, 2016.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.