GIORGI, M., and F. MOLINA. “CAMPO NORMALE E VARIAZIONE SECOLARE MEDIA DEGLI ELEMENTI MAGNETICI IN SICILIA”. Annals of Geophysics 7, no. 4 (November 25, 1954): 521–537. Accessed April 19, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/5714.