Educational Testing Service. (2021). Official guide to the toefl ibt test, sixth edition (Sixth edition.). McGraw Hill.
Chicago-referens (17:e uppl.)Educational Testing Service. Official Guide to the Toefl Ibt Test, Sixth Edition. Sixth edition. New York: McGraw Hill, 2021.
MLA-referens (9:e uppl.)Educational Testing Service. Official Guide to the Toefl Ibt Test, Sixth Edition. Sixth edition. McGraw Hill, 2021.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.