1. Balan, N., Y. Otsuka, T. Tsugawa, S. Miyazaki, T. Ogawa, and K. Shiokawa, Plasmaspheric electron content in the GPS ray paths over Japan under magnetically quiet conditions at high solar activity, Earth Planets Space, 54, this issue, 71–79, 2002.
2. Belwitt, G., An automatic editing algorithm for GPS data, Geophys. Res. Lett., 17, 199–202, 1990.
3. Bilitza, D. (Ed.), International Reference Ionosphere 1990, Rep. NSSDC, 90-22, National Space Science Center, Greenbelt, MD, 1990.
4. Bishop, G. J., A. Mazzella, E. Holland, and S. Rao, Algorithms that use the ionosphere to control GPS errors, in Proceedings of the IEEE 1996 Position Location and Navigation Symposium (PLANS) pp. 145–152, IEEE Press, Piscataway, N. J., 1996.
5. Bishop, G. J., D. S. Coco, N. Lunt, C. Coker, A. J. Mazzella, and L. Kersley, Application of SCORE to extract protonospheric electron content from GPS/NNSS observations, in Proceedings of ION GPS ’97, pp. 207–216, Inst. of Navig., Alexandria, Va., 1997.