Cita APA (7a ed.)
Duckworth, M., O'Neill, R., & Gude, K. (1987). Success at First Certificate. The University Press.
Cita Chicago Style (17a ed.)
Duckworth, Michael, Robert O'Neill, y Kathy Gude. Success at First Certificate. Oxford: The University Press, 1987.
Cita MLA (9a ed.)
Duckworth, Michael, et al. Success at First Certificate. The University Press, 1987.
Precaución: Estas citas no son 100% exactas.