- International Classification of Functioning, Disability, and Healthwww.cdc.gov
- DisabilityMeasures.orgwww.disabilitymeasures.org
- Administration on Intellectual and Developmental Disabilities (AIDD)www.acl.gov
- The Arc of the United States – National/State Chapters for Developmental Disabilitieswww.thearc.org
- American Association on Intellectual and Developmental Disabilities (formerly AAMR)www.aaidd.org