1. Z. Ning, Z. Guanglong, L. Yong, L. Junmin, G. Xiyan, L. Lunhui, C. Jiahua, SAE 952058, 1995.
2. M. Gautam, S. Popuri, B. Rankin, M. Seehra, SAE 993565, 1999.
3. Z. Ning, Y. Yongsheng, SAE 991470, 1999.
4. R.D. Nixdorf, J.B. Green, J.M. Story, R.M. Wagner, SAE010903, 2001.
5. C.P. Garner, J.C. Dent, SAE 905116, 1990.