1. Chen Gang, Zhang Weigong: Chinese Journal of Mechanical Engineering Vol. 21 (2010), p.651.
2. Xie Ya-qing: Machinery Design and Manufacture (2009), p.180.
3. Matsuura S, Shintani Y.: Control and Information Engineers Vol. 5 (1992), p.410.
4. Zhang Jun, Xu Wen, Song Hao: Modular Machine Tool & Automatic Manufacturing Technique. Vol. 8 (2006), p.35.
5. Wang Tingjun: Reston (USA): American Society of Civil Engineers (2009), pp.3675-3680.