Uspensky, M., R. Pellinen, W. Baumjohann, G. Starkov, E. Nielsen, G. Sofko, and K. Kaila. “Spatial Variations of Ionospheric Conductivity and Radar Auroral Amplitude in the Eastward Electrojet Region During Pre-Substorm Conditions”. Journal of Geophysics, Vol. 52, no. 1, Feb. 1983, pp. 40-48, https://journal.geophysicsjournal.com/JofG/article/view/262.