@book{50514,
	author = {Sampson, Geoffrey and Willson, Patricia, },
	title = {Sistemas  de escritura},
	publisher = {Gedisa, },
	year = {1997},
	series = {Lea : Lenguaje-Escritura-Alfabetización ;},
	address = {Barcelona, España : },
	edition = {1a ed.}
}