Digging into Language References

De Villiers, Peter A. and Jill G. (1979). Early Language. Cambridge, MA: Harvard University Press.

Mallery, Garrick. (1972). Sign Language Among North American Indians. The Hague: Mouton.

Riekehof, Lottie, L. (1987). The Joy of Signing, Second Edition. Springfield, MO: Gospel Publishing House.

Tomkins, William. (1969). Indian Sign Language. New York, Dover Publications, Inc.

The World Book Encyclopedia. 1989. Chicago: World Book, Inc.