@book{215862,
	author = {Zill, Dennis G.},
	title = {Ecuaciones diferenciales},
	publisher = {Cengage Learning},
	year = {c2009.},
	address = {México},
	edition = {9th ed.},
	note = {Includes index.},
	url = {http://www.loc.gov/catdir/toc/fy0805/2008924906.html}
}