References
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- . LEVETT, L. M., A Method of Communication for Non-Speaking Severely Subnormal Children. The British Journal of Communication Disorders 1969, 4 pp. 64–66.
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- . SKELLY, M., SCHINSKY, L., SMITH, R. W., DONALDSON, R. C., GRIFFIN, J. M. American Indian Sign: A Gestural Communication System for the Speechless. Arch. Phys. Med. Rehabil. Vol. 56, April, 1975
- . SKELLY, M. American Indian Sign System. Journal of Speech and Hearing Disorders, Vol. 39, No. 4, Nov. 1974, pp. 156–160.