1. Review of the feasibility of underground coal gasification In the UK, cleaner fossil fuels programme, DTI/Pub URN 04/1643.
2. Review of environmental issues of underground coal gasification, Report No. Coal R272 DTI/Pub URN 04/1880, November 2004; Martin Sury et al., unit 5–6.
3. Underground coal gasification: a brief review of current status;Shafirovich;Ind Eng Chem Res,2009
4. Underground coal gasification;Gregg;AIChE J,1978
5. Best practices in underground coal gasification;Burton;Lawrence Livermore National Lab,2005