Cita APA (7th ed.)
Portner, P. (2009). Modality. Oxford University Press.
Cita Chicago (17th ed.)
Portner, Paul. Modality. Oxford ; New York: Oxford University Press, 2009.
Cita MLA (9th ed.)
Portner, Paul. Modality. Oxford University Press, 2009.
Atenció: Aquestes cites poden no estar 100% correctes.