TY  - RPRT
TI  - Variables determining concept conservation in children.
AU  - I E Sigel
AU  - E Saltz
AU  - W Roskind
PY  - 1967
DO  - 10.1037/h0021278
UR  - https://pubmed.ncbi.nlm.nih.gov/6065465/
ID  - 6065465
ER  -