Harris, J. C. (2006). Intellectual disability: Understanding its development, causes, classification, evaluation, and treatment. Oxford University Press.

Harris, James C. Intellectual Disability: Understanding Its Development, Causes, Classification, Evaluation, and Treatment. New York: Oxford University Press, 2006.

Harris, James C. Intellectual Disability: Understanding Its Development, Causes, Classification, Evaluation, and Treatment. Oxford University Press, 2006.