4Pearce N,Weiland S,Keil U,et al.Self-reported prevalence of asthma symptoms in child in Australia,England,Germany and New Zealand:an international comparison using the JSAAC protocol[J].Eur Respir J,1993,6(10):1445-1461.
5World Health Organization.Oral health surveys basic methods[M].3r ed.Geneva:WHO,1987:12-22.