@book{32332,
	author = {Piaget, Jean, 1896-},
	title = {Main trends in inter- disciplinary research /},
	publisher = {Allen & Unwin,},
	year = {c1973.},
	address = {London :},
	note = {Origibally published as Chapter 7 in " Main trends in social and human sciences, part 1, Mouton, Unesco, 1970"}
}