1. Assessment of preverbal communicative abilities in students with severe intellectual disability;Butterfield;Australia and New Zealand Journal of Developmental Disabilities,,1991
2. Corroborating previous findings: Laying stepping stones in the analysis of biobehavioral states in students with profound disabilities;Richards;Education and Training in Mental Retardation,1993
3. Shifting the focus: Emerging priorities in communication programming for students with a severe intellectual disability;Butterfield;Education and Training in Mental Retardation and Developmental Disabilities, March,1995