@book{227316,
	title = {Posibilidad, contingencia, necesidad, existencia},
	publisher = {Eunsa},
	year = {2011.},
	series = {Filosófica},
	address = {Pamplona},
	edition = {1a.ed.},
	note = {Papers presented at a conference organized by the Universidad de Navarra on Dec. 10-11, 2010.}
}