@Book{DGA20070166819, title = "Comentario a los arts. 20.\textordmasculine , 21.\textordmasculine y 22.\textordmasculine ", author = "SAPENA TOM\'{A}S, Joaqu\'{\i}n", URL = "https://derechoaragones.aragon.es/es/consulta/registro.do?id=601641", year = "1988", }