TY  - RPRT
TI  - Piagetian principles: simple and effective application.
AU  - K C Williams
PY  - 1996
DO  - 10.1046/j.1365-2788.1996.711711.x
UR  - https://pubmed.ncbi.nlm.nih.gov/8731468/
ID  - 8731468
ER  -