Reference
- VAN DER VEER , R. 1997 . “ Some major themes in Vygotsky's theoretical work. An introduction ” . In The Collected Works of L. S. Vygotsky. Vol. 3. Problems of the Theory and History of Psychology , Edited by: RIEBER , R.W. and WOLLOCK , J. 1 – 7 . New York-London : Plenum Press .