Makoto Kaneko, Tomohiro Kawahara, Satoshi Matsunaga, Toshio Tsuji, and Shinji Tanaka：Touching Stomach by Air
IEEE International Conference on Robotics and Automation, pp. 664-669, 2003.
Tomohiro Kawahara, and Makoto Kaneko：Non-Contact Stiffness Imager for Medical Application
IEEE International Conference on Information Acquisition, pp. 350-355, 2005.
Tomohiro Kawahara, Satoshi Matsunaga, Shinji Tanaka, and Makoto Kaneko：Non-contact Stiffness Imager
Journal of the RSJ, Vol. 24, No. 3, pp. 363-369, 2006(in Japanese).