Mariani, F. “Variazioni Stagionali E Non Stagionali Della Densità Elettronica Ionosferica”. Annals of Geophysics 10, no. 1-2 (November 25, 1957): 165–181. Accessed April 16, 2026. https://www.annalsofgeophysics.eu/index.php/annals/article/view/5892.