Berry, M.F., & Eisenson, J.Speech disorders, procedures and principles of therapy. New York: Appleton-Century-Crofts, 1956.
2.
Hoffman, M., & Hoffman, L.Review of child development research. Vol. 1. New York : Russell Sage Foundation, 1964, 249-283.
3.
Metraux, R.Auditory memory span for speech sounds: norms for children. Journal of Speech and Hearing Disorders, 1944, 9, 1, 31-38.
4.
Mussen, P. (Ed.) Handbook of research methods in child development. New York: Wiley, 1960.
5.
Silver, A., & Hagin, R.A.Developmental language disability stimulating mental retardation. Journal of the American Academy of Child Psychiarry, 1965, 4, 3, 485-494.