Palmer, F. (1987). The English verb (2nd ed.). Longman.
Cita Chicago (17th ed.)Palmer, F.R. The English Verb. 2nd ed. London: Longman, 1987.
Cita MLA (9th ed.)Palmer, F.R. The English Verb. 2nd ed. Longman, 1987.
Atenció: Aquestes cites poden no estar 100% correctes.