(1) Capsule endoscope system in Japan http://japanest-nippon.com/jp/products/pd_detail.php?id=33
(2) Watada Masaya Kenichi Ozawa, Development of self-propelled mechanism aimed to be incorporated in the capsule endoscope, Japan AEM Journal, Vol.18, No.3, pp251-256 (2010)
(3) Koki Ueno Masaya Watada Akira Mori Examination of locomotive system for capsule endoscope in small intestine MAGDA Conference in Sendai Y-116, pp116(2012)
(4) Takenobu Nakajima Masaya Watada, "Proposal of Wireless Power Supply System for Capsule Endoscope", Asia Pacific Symposium of Applied Electromagnetics and Machanics (APSAEM2010) Proceedings, T08-07, CDR OM, pp.288-2 (2010)
(5) Takao Suzuki:. "Body of Japanese: health and physical data collection", Asakura Shoten, p 57-64(1996)