Sigel, Irving E <br/><br/>
Logical thinking in children; research based on Piaget's theory / 
edited by Irving E. Sigel [and] Frank H. Hooper. With foreword by Bärbel Inhelder  
 - New York :  Holt, Rinehart and Winston,  1968. 
 - xv, 541 p.  illus. 
<br/><br/>Includes bibliographies. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Conservation of substance (Psychology)<br/>Child psychology.
<br/><br/><label>Dewey Class. No.: </label>155.4  / SIG