TY  - BOOK
AU  - Hart,K M.; Brown M,L; Kuchemann,D,E. M.L Brown;
TI  - Children's understanding of mathematics:11-16,
SN  - 9781905200023
AV  - DUCE QA135.5.C478 
PY  - 1981///
CY  - England
PB  - Antony Rowe
N1  - includes appendix,index and reference
ER  -