P. Gao, and H. Han. Proceedings of the 6th International Conference on Ubiquitous Information Management and Communication, page 78:1--78:9. New York, NY, USA, ACM, (2012)
L. ying Ding, Y. gang Li, and F. yu Han. Journal of Qingdao Institute of Chemical Technology, volume 24. Qingdao University of Science and Technology, China, (September 2003)