1. Beijing Will Build 700 “no-coal Villages” by the End of 2017;Beijing Daily,2017
2. The Implementation Scheme of Stop Limit Production for 2017-2018 Years in Beijing City Heating Season Peak Industrial Enterprises (Beijing Economic and Information Committee [2017] No. 359);Beijing Economic and Information Committee (BEIC),2017
3. The Natural Gas Supply Is Improved and Beijing Will Form Three Major Gas Sources;Beijing Morning Post,2017
4. Beijing Statistical Yearbook 2016;BMBS (Beijing Municipal Bureau of Statistics),2016
5. CAEPI (China Association of Environmental Protection Industry), 2016. http://www.caepi.org.cn/p/1210/363343.html, accessed September. 18, 2017 (in Chinese).