TY  - BOOK
AU  - Wallace,J.G.
TI  - Stages and transition in conceptual development : : an experimental study / 
U1  - 155.423 
PY  - 1972///
CY  - Slough : 
PB  - N.F.E.R., 
KW  - Learning, Psychology of
KW  - Concepts
N1  -  Includes bibliographical references (p. 236-243) and indexes
ER  -