1. American Association on Intellectual and Developmental Disabilities (2013) Definition of intellectual disability. Available at: https://www.aaidd.org/intellectual-disability/definition/faqs-on-intellectual-disability (accessed 19 April 2020).
2. Pardon the Interruption
3. Beukelman D, Mirenda P (2013) Chapter 5: Principles of Assessment Augmentative and Alternative Communication: Supporting Children and Adults with Complex Communication Needs, 4th ed. Baltimore, MD: Paul H. Brookes, pp. 101–130.