Concrete Operational Stage

References

Santrock, John W. (2008). A topical approach to life-span development (4 ed.). New York City: McGraw-Hill.

Piaget, J. (1977). Gruber, H.E.; Voneche, J.J. eds. The essential Piaget. New York: Basic Books.

Piaget, J. (1983). Piaget's theory. In P. Mussen (ed). Handbook of Child Psychology. 4th edition. Vol. 1. New York: Wiley.

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