D. R. Themens, P. T. Jayachandran, D. Bilitza, P. J. Erickson, I. Haggstrom, M. V. Lyashenko, B. Reid, R. H. Varney, and L. Pustovalova. Topside electron density representations for middle and high latitudes: A topside parameterization for E-CHAIM based on the NeQuick. Journal of Geophysical Research: Space Physics, American Geophysical Union, volume 123, 2018 . J. J. Sojka, M. Nicolls, A. van Eyken, C. Heinselman, and D. Bilitza. 24/7 Solar minimum polar cap and auroral ion temperature observations. Advances in Space Research, volume 48, 2011 .