Journal Article:

Roche, L., Sigafoos, J., Lancioni, G., O'Reilly, M., van de Meer, L., Achmadi, D., Green, V., Kagohara, D., Sutherland, D., Rayner, C. & Marschik, P. (2013). Comparing tangible symbols, picture exchange, and a direct selection response for enabling two boys with developmental disabilities to access preferred stimuli. Journal of Developmental and Physical Disabilities, Vol. 26, No. 3 249-261.