@book{223551,
	author = {Garfinkle, David and Garfinkle, Richard.},
	title = {El universo en tres pasos},
	publisher = {Crítica},
	year = {2010.},
	address = {Barcelona},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/enhancements/fy0829/2008008659-d.html}
}