1. Lloyd, L. L. & Karlan, G. R. (1982, August). Nonspeech communi-cation symbols and systems: Where have we been and where are we going? Journal of Mental Deficiency Research, 28, 3-20. (An invited plenary presentation at the Vlth Congress of the Interna-tional Association for the Scientific Study of Mental Deficiency, Toronto.)
2. Lloyd, L. L. & Karlan, G. R. (1983, August 14-18). Nonspeech communication symbol selection considerations. In the Proceed-ings of the XIX Congress of the International Association of Logo-paedics and Phoniattics, Universiy of Edinburgh, Scotland.