MARCELLI, L., and M. C. SPADEA. “La Profondità Ipocentrale Con Metodi Macrosismici”. Annals of Geophysics 34, no. 1 (November 25, 1981): 5–36. Accessed October 25, 2021. https://www.annalsofgeophysics.eu/index.php/annals/article/view/4684.