1. National Bureau of Statistics of China http://www.stats.gov.cn/tjgb/rkpcgb/qgrkpcgb/t20020331_15434.htm
2. National Bureau of Statistics of China http://www.stats.gov.cn/tjgb/rkpcgb/qgrkpcgb/t20060316_402310923.htm
3. The current state of public health in China;Lee;Annu Rev Public Health,2004
4. Ministry of Health of China 2004 http://www.moh.gov.cn/statistics/digest04/tt.htm