1. 1. K. Sagawa, K. Koiwa, M. Susumago, H. Inooka, ―Estimation of an indoor 3D walk course by acceleration integration‖, 22th Joint Conference on Medical Information Japan Journal of Medical Informatics 22, pp.242-243, Nov. 2002.
   2. M. Yamamoto, E. Kamioka, ―Location Estimation System using Acceleration Sensor‖, The Institute of Electronics, Information, and Communication Engineers Technical Report, Mobile Network and Applications, vol.110, no.40, pp.139-144, May. 2010.
   3. M. Kourogi, T. Kurata, ―Personal Positioning Based on Walking Locomotion Analysis with Self-Contained Sensors and a Wearable Camera‖, in Technical Report of The Institute of Electronics, Information, and Communication Engineers Technical Report, PRMU 103(737), pp.25-30, Mar. 2004.
   4. N. Kawaguchi, ―Locky.jp: Wireless LAN Position Estimation and Its Application‖, The Institute of Electronics, Information, and Communication Engineers Technical Report, ITS vol.107, no.161, pp.1- 4, Jul. 2007.
   5. Y. Yokota, T. Hitoyasu, M. Miki, H. Yokouchi, M. Yoshimi, ―Location Estimation in Indoor Environment based Distribution of the RSS‖, in Proc. the Annual Conference of The Japanese Society for Artificial Intelligence, vol.24, no.3C2-2, pp.1–4, Jun. 2010
   6. Research Committee on the use of radio waves for regional development, ―Research Report on Telecommunications in the Hospital‖, p.8, Mar. 2002.
   7. ―Daitoshi Iryo Crisis 1.‖, NHK ONLINE, Dec. 20, 2012 http://www.nhk.or.jp/ohayou/marugoto/2012/12/1220.h tml , accessed Nov.7, 2013.
   8. K. Anzai, S. Okajima, H. Tsubokawa, ―The estimate of the indoor position that used a smartphone and the suggestion of the walk navigation system‖, in Multimedia, Distributed, Cooperative, and Mobile Symposium 2011, pp..921-927, July 2011.
   9. T. Takakai, M. Fujii, Y. Watanabe, A. Ito, ―A Study on Location Awareness System using cellular phone with Bluetooth‖, The Institute of Electronics, Information, and Communication Engineers Technical Report ITS, vol.108, no.205, pp.31-36, Sep. 2008.
   10. Medsafe.Net. ―Utilizing PHS for communication tools in hospital‖, Medsafe.Net, Nov.21, 2006 http://www.medsafe.net/contents/recent/- 107jikeikai.html , accessed Mar.26, 2013.
   11. Y. Uramoto, S. Kitamura, ―Examination of simplified position information acquisition depending on PHS utilization‖, in Proc. The Institute of Electronics, Information, and Communication Engineers General Conference, no.B-5-138, p.525, Mar. 1997.
   12. H. Ookura, H. Yamamoto, K. Yamazaki, ―Development and evaluation of walking path estimation system using sensors of Android device and vector map matching‖, in Proc. The Institute of Electrical and Electronics Engineers, The International Conference on Information Networking.2012, pp.25-29, Feb. 2012.
   13. K. Katsuhiko, N. Kawaguchi, ―Gate-Passing Detection Method Based on WiFi Significant Points‖, in Proc. of the World Congress on Engineering 2013, Voll.II, pp.1409-1414. July 2013.
   14. R. Aoki, H. Yamamoto, K. Yamazaki, ―Realtime Guidance System in Hospital using PHS and Android Device‖, in Proc. The Institute of Electrical and Electronics Engineers, Computer Software and Applications Conference 2013, pp.451-454, July 2013.
   15. H. Ito, ―The Status of the Navigation and Route Guidance System in Foreign Countries and Their Standardization Activities‖, The International Association of Traffic and Safety Sciences Review, Vol.26, No.4, pp.232-242, Sep. 2001.
   16. Ryoji Aoki, Hiroshi Yamamoto, Katsuyuki Yamazaki, ― Android- based Navigation system for Elderly People in Hospital‖, The Nagoka Unversity of technology, pp March 2014.