Upgrades to the topside sounders model assisted by Digisonde (TaD) and its validation at the topside ionosphereAnna Belehaki, Ioanna Tsagouri, Ivan Kutiev, Pencho Marinov and Stefka FidanovaJ. Space Weather Space Clim., 2 (2012) A20DOI: https://doi.org/10.1051/swsc/2012020
