O'Connor, N., & Hermelin, B. (1963). Speech and thought in severe subnormality: An experimental study. Macmillan.
Dyfyniad Arddull ChicagoO'Connor, N., and Beate Hermelin. Speech and Thought in Severe Subnormality: An Experimental Study. New York: Macmillan, 1963.
Dyfyniad MLAO'Connor, N., and Beate Hermelin. Speech and Thought in Severe Subnormality: An Experimental Study. Macmillan, 1963.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.