1. International reference ionosphere 2000: examples of improvements and new features;Bilitza;Adv. Space Res.,2003
2. Davis, R.M., Groome, N.L. Variations of the 3000 km MUF in time and space, NBS Report 8498, US Department of Commerce, 1964
3. Variability of the ionosphere;Forbes;J. Atmos. Solar-Terr. Phys.,2000
4. Fox, M.W., Wilkinson, P.J. A study of OWF conversion factors in the Australian region. IPS Technical Report, IPS-TR-88-02, March 1988
5. An empirical ionospheric storm-time correction model;Fuller-Rowell;Adv. Space Res.,2000