@book{20614,
	author = {Atienza, Manuel and Ruiz Manero, Juan},
	title = {Las piezas del derecho  Teoría de los enunciados jurídicos},
	publisher = {Ariel},
	year = {1996},
	series = {Ariel Derecho},
	address = {Barcelona (España)},
	edition = {1a. ed.}
}