1. Heng Sun, Zuomo Chen: Mechanical Principles(Higher Education Press, Beijing 2001), in Chinese.
2. Lianggui Pu, Minggang Ji: Mechanical Design(Higher Education Press, Beijing 2004), in Chinese.
3. X. S. Wang, Y. Li, Y. C. Yu: Advanced Material Research Vol. 139-141(2010), pp.1093-1096.
4. X. S. Wang, Y. Li, Y. C. Yu: Advanced Material Research Vol. 97-101(2010), pp.3211-3214.