TY  - BOOK
AU  - Inhelder,Barbel
AU  - Piaget,Jean
TI  - The early growth of logic in the child : : classification and seria tion  / 
U1  - 155.413 
PY  - 1964///
CY  - London : 
PB  - Routlegde & Kegan Paul, 
KW  - Child study
KW  - Logic
ER  -