Z. Yang, G. Pedersen, L. Larsen, and H. Thybo. Proceedings of 33rd Annual Conference of the IEEE Industrial Electronics Society (IECON'07), page 574--579. Taipei, Taiwan, Electrical Engineering/Electronics, Computer, Communications and Information Technology Association, (2007)
Z. Yang, G. Pedersen, and J. Pedersen. Proceedings of the 13th IEEE/IFAC International Conference on Methods and Models in Automation and Robotics, page 723--729. Szczecin, Poland, IEEE, (2007)