1. 1) N. Muramatsu and H. Akiyama: Japan: Super Aging Society Preparing for the Future, The Gerontologist, 51-4, 425/432 (2011)
2. 2) D. Ding and R.A. Cooper: Electric Powered Wheelchairs, IEEE Control Systems Magazine, 25-2, 22/34 (2005)
3. 3) K. Matsumoto, M. Ishikawa, M. Inaba and I. Shimoyama: Assitive Robotic Technologies for an Aging Society, Outline of Information and Robot Technology Research Initiative, The University of Tokyo, http://www.irt.i.u-tokyo.ac.jp/en/outline/index.shtml (accessed Feb. 12, 2021)
4. 4) Y. Matsumoto, T. Ino and T. Ogasawara: Development of intelligent wheelchair system with face and gaze based interface, Proceedings of 10th IEEE International Workshop on Robot and Human Interactive Communication, 262/267 (2001)
5. 5) M. Nishimori, T. Saitoh and R. Konishi: Voice Controlled Intelligent Wheelchair, Proceedings of SICE Annual Conference 2007, 336/340 (2007)