BeamerR. H.LemkeE. A.Effects on transfer of training of constant versus varied training, group size, and ability level, in elementary school mathematics. Journal for Research in Mathematics Education, 1973, 4, 20–25.
2.
HarlowH. F.Learning set and error factor theory. In KochS. (Ed.), Psychology: A study of a science. New York: McGraw-Hill, 1959. Pp. 492–537.
