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. 24 cm.
Includes bibliographies.
Piaget, Jean, 1896-1980.
Conservation of substance (Psychology) Child psychology.