Van Ek, J. (1988). Threshold level English in a European unit/credit system for modern language learning by adults. Prentice-Hall.
Chicago Style (17. basım) AtıfVan Ek, J. Threshold Level English in a European Unit/credit System for Modern Language Learning by Adults. New York: Prentice-Hall, 1988.
MLA (9th ed.) AtıfVan Ek, J. Threshold Level English in a European Unit/credit System for Modern Language Learning by Adults. Prentice-Hall, 1988.
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