Fact Sheet: Mental Retardation
- Definition, causes, diagnosis, and information from the National Information Center for Children and Youth with Disabilities.
- http://www.nichcy.org/pubs/factshe/fs8txt.htm

KidsHealth: Mental Retardation
- Provides a definition, suspected causes, and what life is like for someone who is mentally retarded.
- http://www.kidshealth.org/kid/health_problems/birth_defect/mental_retardation.html