Kass, C. E., and Johnson, M.: Paradoxical values in learning disabilities. J. Learning Disabil., 1972, 5(8), 463–466.
2.
Kass, C. E., and Myklebust, H. R.: Learning disability: an educational definition, J. Learning Disabil., 1969, 2(7), 377–379.
3.
McDonald, C. W.: Problems concerning the classification and education of children with learning disabilities. In J. Hellmuth: Learning Disorders, Vol. III. Seattle: Special Child Publ.
4.
Myers, P. I., and Hammill, D. D.: Methods for Learning Disorders. New York: John Wiley1969.
5.
Siegal, S.: Nonparametric Statistics for the Behavioral Sciences. New York: McGraw-Hill, 1956, p. 229–238.
6.
Zach, L. and Kaufman, J.: How adequate is the concept of perceptual deficit for education?J. Learning Disabil., 1972, 5(6), 351–356.
