1. Future Energy: Improved, Sustainable and Clean Options for Our Planet;Letcher,2008
2. Annual Energy Outlook 2013 with Projections to 2040,2013
3. 21st Century Coal Advanced Technology and Global Energy Solution,2013
4. Influence of coal as an energy source on environmental pollution;Balat;Energy Sources Part A Recovery Util. Environ. Eff.,2007
5. World Energy Outlook 2013,2013