Soars, J. &. L. (1996). Headway: Elementary(student's book) (7a ed.). Oxford University Press.
Chicago Style (17th ed.) CitationSoars, John & Liz. Headway: Elementary(student's Book). 7a ed. Oxford, Inglaterra: Oxford University Press, 1996.
MLA (9th ed.) CitationSoars, John & Liz. Headway: Elementary(student's Book). 7a ed. Oxford University Press, 1996.