Cita APA (7th ed.)
Soars, J., & Soars, L. American Headway: Student Book 4. Oxford University.
Cita Chicago (17th ed.)
Soars, John, i Liz Soars. American Headway: Student Book 4. Nueva York, EUA: Oxford University.
Cita MLA (9th ed.)
Soars, John, i Liz Soars. American Headway: Student Book 4. Oxford University.
Atenció: Aquestes cites poden no estar 100% correctes.