@book{803,
	author = {Piaget, Jean,},
	title = {Main trends in inter-disciplinary research /},
	publisher = {Allen & Unwin,},
	year = {1973.},
	address = {London :},
	note = {"Originally published as chapter 7 in Main trends of research in the social and human sciences, part 1, Mouton/Unesco, 1970.".}
}