1. American Psychiatic Association. (1980). Diagnostic and statistical manual. Washington, DC: APA Press.
2. American Psychiatric Association. (1987). Diagnostic and statistical manual. Washington, DC: APA Press.
3. Gillberg, C. (1991). Debate and argument: Is autism a pervasive developmental disorder? Journal of Child Psychology and Psychiatry, 32(7), 1169–1170.
4. Heller, T. (1908). Dementia infantilis. Zeitschrift fur die Erforschung und Behandlung des Jugenlichen Schwachsinns, 2, 141–165.
5. Heller, T. (1930). Uber dementia infantilis. Zeitschrift fur Kinderforschung, 37, 661–667.