1. E. L. Afraimovich and E. I. Astaf’eva, “Morphology and Dynamics of Isolated Ionospheric Inhomogeneities according to the GPS Network Data,” Soln.-Zemn. Fiz., No. 3, 50–60 (2002).
2. E. L. Afraimovich and N. P. Perevalova, GPS-Monitoring of the Earth’s Upper Atmosphere (GUNTs RVKh VSNTs SO RAMN, Irkutsk, 2006) [in Russian].
3. S. V. Bilichenko, A. S. Inchin, E. F. Kim, O. A. Pokhotelov, G. A. Stanev, P. P. Puschaev, A. V. Streltsov, and V. M. Chmyrev, “ULF Ionospheric Response to Earthquake Preparation Processes,” Dokl. Akad. Nauk SSSR 311(5), 107–108 (1990).
4. E. Blanc, “Observations in the Upper Atmosphere of Infrasonic Waves from Natural or Artificial Sources. A Summary,” Ann. Geophys. 3, 673–679 (1985).
5. N. Borisov, V. Chmyrev, and S. Rybachek, “A New Ionospheric Mechanism of Electromagnetic ELF Precursors to Earthquakes,” J. Atmos. Sol.-Terr. Phys. 63, 3–10 (2001).