V. Majuntke, G. Schiele, K. Spohrer, M. Handte, and C. Becker. Proceedings of the Sixth International Conference on Intelligent Environments (IE 2010), Kuala Lumpur, Malaysia, page 178--184. Los Alamitos, CA, IEEE Computer Society CPS, (2010)
Z. Cherif, A. Nait-Ali, J. Motsch, and M. Krebs. Proceedings of the19th IEEE Instrumentation and Measurement Technology Conference (IMTC 2002), Anchorage, AK, USA, 2, page 1029--1033. (2002)