TY  - BOOK
AU  - Lesh,  Richard.
TI  - Beyond constructivism: models and modeling perspectives on Mathematics problem s
SN  - 805838228
U1  - 510.71 BEY 
PY  - 2003///
CY  - London
PB  - Lawrence Erlbaum Associates, Publishers
N1  - Includes bibliographical references
ER  -