[1] Z. P. Jin, “Study on Soil and Water Conservation and Agriculture Development in Soft Sandstone Area,” Yel-low River Conservancy Press, Zhengzhou, 2003.
[2] Y. C. Wang, Y. H. Wu and M. Li, “Study on Status of Soil and Water Losses and Harnessing Way in Soft Sand-stone Area,” Yellow River Conservancy Press, Zheng-zhou, 2007.
[3] Y. S. Zhong, “Marcov Chain and Its Utilization in For-estry Prediction,” Journal of Northwest Forestry College, Vol. 3, No. 1, 1998, pp. 75-81.