1. J. Sha X.L. Chang and G. Cai: Manufacturing Technology and Machine Tools. No. 11, pp.109-112.
2. A.L. Wang J.T. Zhang and Y. Wu: principles of Modern CNC and Control System(National Defence Industry Press, China 2002).
3. W. Lu, J.Z. Fu: Machine Tool & Hydraulics. No. 9, pp.219-221(2006).
4. XIE Ou, LI Hua, YIN Zhen, LI Zhen and ZHANG Zhiwei: Manufacturing Technology & Machine Tool. Vol. 6 (2010), p.36.
5. O. Xie, H, Li and Y. Li: Key Engineering Materials. Vol. 416. pp.34-39(2009).