TY  - BOOK
AU  - Spencer,Peter Lincon
AU  - Brydegaard,Marguerite
TI  - Building mathematical concepts: : in elementary school 
AV  - QA 107 S64 1952 
PY  - 1952///
CY  - New York : 
PB  - Henry Holt, 
KW  - Matemáticas
KW  - Conceptos
N1  - Includes index
ER  -