Lombardo, G., G Coco, M. Corrao, and S. Gresta. “Features of Seismic Events and Volcanic Tremor During the Preliminary Stages of the 1991-1993 Eruption of Mt. Etna”. Annals of Geophysics 39, no. 2 (November 25, 1996). Accessed July 7, 2022. https://www.annalsofgeophysics.eu/index.php/annals/article/view/3974.