@book{44227,
	author = {Piaget, Jean and Petit, Nuria},
	title = {Seis estudios de psicología / },
	publisher = {Editorial Seix Barral , },
	year = {1977 . },
	series = {Biblioteca breve. Ensayo},
	address = {Barcelona : },
	edition = {9a. ed.},
	note = {Incluye índice. }
}