1. United Nations: World Population Ageing 2019 (2019). Available online: https://www.un.org/en/development/desa/population/theme/ageing/index.asp
2. Kono, J., Inada, J.: Special characteristics of tooth brushing movement in elementary school and the elderly. Jpn. Soc. Dent. Health 58(3), 91–92 (1995)
3. Simpson, R., Levine, S.: Adaptive shared control of a smart wheelchair operated by voice control. In: Proceedings of IEEE International Conference on Intelligent Robots and Systems, pp. 91–92 (1997)
4. Ichinose, Y., Wakumoto, M., Honda, K. et al.: Human interface using a wireless tongue-palate contact pressure sensor system and its application to the control of an electric wheelchair. Trans. Inst. Electron., Inf. Commun. Eng. J86-D-II(2), 364–367 (2003)
5. Moon, I., Lee, M., Chu, J. et al.: Wearable EMG-based HCI for electric-powered wheelchair users with motor disabilities. In: Proceedings of the 2005 IEEE International Conference on Robotics and Automation, pp. 2649–2654 (2005)