HeberR.A manual in terminology and classification in mental retardation. American Journal of Menial Deficiency, Monograph Supplement (2nd ed.), April 1961.
2.
KirejczykK.Poor achievers in elementary schools. New School, 1971; 6, 16–21.
3.
LipkowskiO.Special education within a system of public education. New School, 1971; 6, 8–15.
4.
PevznerM. Z.Etiopathogenesis and classification of oligophrenia. (Trans, by G. Malawko)Szkola Specjalna.1970; 4, 289–293.
5.
VlasovaT. A., & PevznerM. Z.For teachers about children with developmental anomalies.Moscow: Academy of Pedagogical Sciences, 1967.
6.
WaldI.Etiology of mental retardation. New School, 1971; 6, 32–36.
7.
ZarandiaM. I.On the development of mental operations in the children of pre-school age. Voprosy Psychologii, 1971; 5, 100–109.