1. 1) Okamoto, S., Nagano, H. and Yamada, Y.：IEEE Transactions on Haptics, 6 (1), 81 (2013)
2. 2) Tachi, S., Minamizawa, K., Furukawa, M. and Fernando, C. L.：Proceedings of 2013 23rd International Conference on Artificial Reality and Telexistence, 145 (2013)
3. 3) Hashim, I. H. M., Kumamoto, S., Takemura, K., Maeno, T., Okuda, S. and Mori, Y.：Sensors, 17 (11), 2601 (2017)
4. 4) Robles-De-La-Torre, G. and Hayward, V.：Nature, 412, 445 (2001)
5. 5) Winfield, L., Glassmire, J., Colgate, J. E. and Peshkin, M.：Proceedings of Second Joint EuroHaptics World Haptics Conf., 2007., 421 (2007)