@book{4604,
	author = {Cunningham, F. Gary and Cunningham, F. Gary.},
	title = {Williams obstetricia /},
	publisher = { McGraw-Hill,},
	year = { 2011.},
	address = {México, D. F. :},
	edition = {Vigésima tercera edición.},
	note = {Incluye índice}
}