Epidemiological survey and risk factor analysis of asthma in children in urban districts of Zhengzhou, China
ZHAO Kun, SONG Gui-Hua, GU Hua-Qian, LIU Shuang, ZHANG Yan, GUO Yan-Rong
CJCP . 2014, (12): 1220 -1225 .  DOI: 10.7499/j.issn.1008-8830.2014.12.007