1. Zhang, X., Zhang, S., Zhong, L., Coalbed Methane in China (in Chinese), Xi’an: Shanxi Science and Technology Press, 1991, 30–64.
2. Liu, C., Yang, S., Experimental research on adsorption regulation of the coal adsorbing methane system, Safety in Coal Mines (in Chinese), 1992, 22(4): 1–5.
3. Qian, K., Zhao, J., Wang, Z., Coalbed Methane Exploration and Development Theory and Experimental Testing Technology (in Chinese), Beijing: Petroleum Industry Press, 1996, 119–142.
4. Nie, B., Duan, S., The adsorption essence of gas on coal surface (in Chinese), Journal of Taiyuan University of Technology, 1998, 29(4): 417–421.
5. Zhang, Q., Yang, X., Isothermal adsorption of coals on methane under equilibrium moisture, Journal of China Coal Society (in Chinese), 1999, 24(6): 566–570.