GelmanR.Conservation acquisition: a problem of learning to attend to relevant attributes. Journal of Experimental Child Psychology, 1969, 7, 67–87
2.
LaPointK., & O'DonnellJ. P.Number conservation in children below age six: its relationship to age, perceptual dimensions and language comprehension. Developmental Psychology, 1974, 10, 422–428
3.
LawsonG. Y.Methodology in developmental psychology: an examination of research on Piagetian theory. Child Development, 1977, 48, 1160–1166
4.
PiagetJ.Quantification, conservation and nativism. Science, 1968, 162, 976–979
5.
PiagetJ.The future of developmental child psychology. Journal of Youth and Adolescence, 1974, 3, 87–93
