1. Boulton, P. I., Paau, R. andSmith, K. C. (1969) A typewriting system for the seriously handicapped. Digest Int. Electronics Conference, Toronto, 48–49.
2. Cairns, R. A. (1969) Touch operated selector control. Personal communication.
3. Cairns, R. A. andJousse, A. T. (1966) Touch operated selector controls—TOSC.Med. Service J. Can. 22, 714–718.
4. Jenkins, R. (1967)Possum: A new communication aid.Special Educ. 56, 9–11.
5. King, V. C. (1963) Project Harold. Northern Electric Co., R & D Laboratories, Ottawa. Personal communication.