TY  - BOOK
AU  - Isaacs, Nathan
TI  - New light on children's ideas number: the work of professor Piaget 
AV  - BF 723.N8 I83
PY  - 1960///
CY  - London
PB  - Ward lock Educational
KW  - Piaget, Jean,
KW  - Psicología infantil
KW  - Concepto de número
ER  -