1. “Conditions Required for Equilibrium of overlying strata at working areas”;Ming-Gao;Journal of China Institute of Mining Technology,1981
2. Li hon-zhang, Chien Ming Gao “A study of the system of the exploitation in upward order in Dai-Tun coal mine”. 1981.
3. King, H.I., Whittaker, B.N. and Batchelor, A.S. “The effects of interaction in mine layouts”. 5th Inter. Strata Control Conf. 1972, London. Proceedings of European Congress on Ground Movement. 1957
4. “Roof control through beam action and arching.”;Wright,1973