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Schalock, Robert L., Ruth Luckasson, and Marc J. Tassé. Intellectual Disability: Definition, Diagnosis, Classification and Systems of Supports. 12th Edition. Silver Spring, MD., USA: American Association on Intellectual and Developmental Disabilities, 2021.

Schalock, Robert L., et al. Intellectual Disability: Definition, Diagnosis, Classification and Systems of Supports. 12th Edition. American Association on Intellectual and Developmental Disabilities, 2021.