BarkerJ.Arizona Articulation Proficiency Scale. Los Angeles: Western Psychological Services, 1963.
2.
BarkerJ., & EnglandG.A numerical measure of articulation: Further developments. Journal of Speech and Hearing Disorders, 1962, 27, 23–28.
3.
FraserD. A. S.Statistics: An introduction. New York: John Wiley & Sons, Inc., 1958.
4.
FudalaJ. B.Arizona Articulation Proficiency Scale. (Rev. ed.) Los Angeles: Western Psychological Services, 1970.
5.
SheaW. L.The effect of supplemental parental procedures on public school articulatory cases. Unpublished doctoral dissertation, University of Florida, 1955.
6.
SommersR. K.Factors in effectiveness of mothers trained to aid in speech correction. Journal of Speech and Hearing Disorders, 1962, 27, 178–186.
7.
TuftsL. C., & HollidayA. R.Effectiveness of trained parents as speech therapists. Journal of Speech and Hearing Disorders, 1959, 25, 395–401.
8.
Van RiperC.. Speech correction: Principles and methods. (3rd ed.) New York: Prentice-Hall, 1954.