BIAGI, P. F. “On Time-Distance Curves for Pn Waves in the Friuli Earthquake of 6 May 1976”. Annals of Geophysics 32, no. 1 (November 25, 1979): 27–35. Accessed April 24, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/4728.