@book{2977,
	author = {Elementos de Lógica.},
	title = {Elementos de Lógica.},
	publisher = {USAC., Facultad Ciencias Económicas,},
	year = {1991.},
	series = {Colección Textos Filosóficos No. 13},
	address = {Guatemala:},
	edition = {1a.}
}