1. In-Sight, an assessment procedure for higher levels of visual functioning in partially sighted children, six to twelve years of age, with normal learning capacities;Ekkens,2002
2. The tactual profile;Withagen,1999
3. The Senses Considered as Perceptual Systems;Gibson,1966
4. The Psychology of Touch;Heller,1991
5. Hands on: haptic exploratory strategies in children who are blind with multiple disabilities;McLinden;British Journal of Visual Impairment,1999