@book{22051,
	author = {Darwin, Charles, and Leakey, Richard E.},
	title = {El origen de las especies /},
	publisher = {Porrúa },
	year = {2004.},
	series = {Sepan cuantos..;},
	address = {México },
	edition = {9a ed.},
	note = {Incluye índice.}
}