GallagherJ.A comparison of brain injured and non-brain injured mentally retarded children on several psychological variables. Monogr. Soc. Res. Child Developm., 1957, 22, No. 65.
2.
SabaghG.DingmanH.TarjanG.WrightS.Social class and ethnic status of patients admitted to a state hospital for the retarded. Pacific sociol. Rev., 1959, 2, 76–80.
3.
ZiglerE.Social deprivation and rigidity in the performance of feebleminded children. J. abnorm. soc. Psychol., 1961, 62, 413–421.