Sigel, I. E., & Cocking, R. R. (1977). Cognitive development from childhood to adolescence: A constructivist perspective. Holt, Rinehart and Winston.
Chicago-viite (17. p.)Sigel, Irving E., ja Rodney R. Cocking. Cognitive Development from Childhood to Adolescence: A Constructivist Perspective. New York: Holt, Rinehart and Winston, 1977.
MLA-viite (8. p.)Sigel, Irving E., ja Rodney R. Cocking. Cognitive Development from Childhood to Adolescence: A Constructivist Perspective. Holt, Rinehart and Winston, 1977.
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