@book{13580,
	author = {Ren-Ying, Yan... [et al.]. and McCarthy, Brian J.},
	title = {The risk approach in perinatal health : Shunyi Country, People's Republic of China.},
	publisher = {U. S. Centers for Disease Control,},
	year = {1989.},
	address = {Atlanta, Ga. : }
}