Cita APA (7th ed.)

Palmer, F. R. (1990). Modality and the English modals. Longman.

Cita Chicago (17th ed.)

Palmer, Frank Robert. Modality and the English Modals. London: Longman, 1990.

Cita MLA (9th ed.)

Palmer, Frank Robert. Modality and the English Modals. Longman, 1990.