1. 1) R. Kuc and B. Barsham: Docking Mobile Robots Using A Bat like Sonar, International Conference on Intelligent Robots and Systems, 2, 1439/1444 (1992)
2. 2) D. Langer and C. Thorpe: Sonar based Outdoor Vehicle Navigation and Collision Avoidance, International Conference in Intelligent Robots and Systems, 1445/1450 (1992)
3. 3) W.D. Rencken and Siemens AG: Autonomous sonar navigation in indoor, unknown and unstructured environment, International Conference in Intelligent Robots and Systems, 1, 431/438 (1994)
4. 5) H. Mori, S. Kotani and N. Kiyohiro: HITOMI: Design and Development of a Robotic Travel Aid, Assistive Technology and Artificial Intelligence Lecture Notes in Computer Science 1458, 221/234 (1998)