1. Shengwu. Xu: Hydraulics Pneumatics & Seals. 02 (2005), p.7.
2. Dongming Hu, Bing Xu, Huayong Yang: Journal of Zhejiang University (Engineering Science). 02(2008), p.209.
3. Rongchuan Lin: Science Technology and Engineering. 10(2010), p.2539.
4. Jiangfeng Hu, Xiaoyi Wu, Zhe Zhao, Ji Fan: Measurement & Control Technology. 02 (2009), p.39.
5. Ye Zhu, Xuyong Wang, Jianfeng Tao, Shu Yan: Journal of Shanghai Jiaotong University. 02 (2008), p.266.