Palmer, F. R. (1990). Modality and the English modals. Longman.
Dyfyniad Arddull ChicagoPalmer, Frank Robert. Modality and the English Modals. London: Longman, 1990.
Dyfyniad MLAPalmer, Frank Robert. Modality and the English Modals. Longman, 1990.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.