Amato, A., R. Azzara, A. Basili, C. Chiarabba, M. Cocco, M. Di Bona, and G. Selvaggi. “Main Shock and Aftershocks of the December 13, 1990, Eastern Sicily Earthquake”. Annals of Geophysics, vol. 38, no. 2, Nov. 1995, doi:10.4401/ag-4122.