From the Centers for Disease Control and Prevention. National poliomyelitis immunization days--People's Republic of China, 1993.
D000846:Anniversaries and Special Events; D002681:China; D006801:Humans; D017589:Immunization Programs; D011051:Poliomyelitis / Q000517:prevention & control*; D011055:Poliovirus Vaccine, Oral
D011055:Poliovirus Vaccine, Oral