@book{100045,
	author = {Schopenhauer, Arthur, and Unamuno, Miguel de,},
	title = {Sobre la voluntad en la naturaleza /},
	publisher = {Alianza Editorial,},
	year = {2006.},
	address = {Madrid :},
	edition = {1. ed.},
	note = {Título original: Uber die Wille in der Natur.}
}