@book{174121,
	author = {Schopenhauer, Arthur, and Unamuno y Jugo, Miguel de,},
	title = {Sobre la voluntad en la naturaleza},
	publisher = {Alianza Editorial},
	year = {c1970.},
	series = {El libro de bolsillo ; 230 : Sección Clásicos},
	address = {Madrid}
}