1. 1. Saad Z. Nagi, Disability and Rehabilitation (Columbus: Ohio State University Press, 1969), pp. 10-15;
2. World Health Organization , International Classification of Impairments, Disabilities and Handicaps (Geneva: World Health Organization, 1980), pp. 11-14.
3. 4. Department of Health and Human Services, Social Security Handbook 1984 (Washington, DC: Government Printing Office, 1984), pp. 75-77.