Cherry. C., Creative movement for the developing child, Fearon Publ. , Palo Alto, Calif., 1968.
2.
Elkonin D., Symbolics and its functions in the play of children, In: Heron R. E. and Sutton-Stmith B. (ed.), Child's play, Wiley, New York, pp. 221—230, 1971.
3.
Lieberman J.N. , Playfulness and divergent thinking: An investigation of their relationship at the kindergarten level, "Journal of Genetic Psychology", 107, pp. 219—224, 1965.
4.
Liikanen P., The combination ability based on play of pre-school children as a developmental diagnostic frame of reference, Rep. Dept. Psychol., Uriiv. Jyväskylä, No. 89, 1969.
