Settimi, Alessandro. “An in-Depth Analysis on the Quasi-Longitudinal Approximations Applied to Ionospheric Ray-Tracing, Oblique and Vertical Sounding, and Absorption”. Annals of Geophysics 65, no. 1 (March 24, 2022): PA103. Accessed May 22, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/8728.