中国空气污染：一年三千亿美元医疗代价 (Air pollution costs China $300 billion per year in medical expenses)
British Broadcasting Corporation, March 25, 2014
www.bbc.co.uk/zhongwen/simp/china/2014/03/140325_china_urbanisation_health.shtml
China's Hangzhou latest city to restrict car sales
Reuters, March 25, 2014
www.reuters.com/article/2014/03/25/us-china-autos-regulations-idUSBREA2O0S620140325