TY  - BOOK
AU  - Sarama, Julie: Clements Douglas H
TI  - Early childhood mathematics education research : learning trajectories for young children
U1  - 372.7/Sar/Cle 
PY  - 2009///
CY  - Newyork
PB  - Routledge
N1  - NTB; PG
ER  -