High-Speed Adaptive Control of a Robot Manipulator. - Yohji Okada; Eiichi Suzuki; Kenichi Matsuda (J. Robotics Mechatronics, 1990)

Levitation and torque control of internal permanent magnet type bearingless motor. - Yohji Okada; Shigenobu Miyamoto; Tetsuo Ohishi (IEEE Trans. Control. Syst. Technol., 1996)