Soars, J. &. L. (1991). Headway: Pre-intermediate(student's book). Oxford University Press.
Chicago Style (17th ed.) CitationSoars, John & Liz. Headway: Pre-intermediate(student's Book). Oxford, Inglaterra: Oxford University Press, 1991.
MLA (9th ed.) CitationSoars, John & Liz. Headway: Pre-intermediate(student's Book). Oxford University Press, 1991.