@book{729,
	author = {Ginsburg, Herbert. and Opper, Sylvia,},
	title = {Piaget's theory of intellectual development /},
	publisher = {Prentice-Hall,},
	year = {c1979.},
	address = {Englewood Cliffs, N.J. :},
	edition = {2d ed.},
	note = {Includes index.}
}