Athanasiou, M. A., G. C. Anagnostopoulos, C. N. David, and G. G. Machairides. “The Ultra Low Frequency Electromagnetic Radiation Observed in the Topside Ionosphere above Boundaries of Tectonic Plates”. Research in Geophysics, vol. 4, no. 1, Jan. 2015, doi:10.4081/rg.2014.5001.