Cimarelli, Corrado, and Donatella De Rita. “Deep-Seated Gravitational Slope Deformations in Volcanic Settings: Examples from Italian Volcanoes”. Geografia Fisica E Dinamica Quaternaria, vol. 33, no. 2, Dec. 2010, pp. 155-64, https://www.gfdq.glaciologia.it/index.php/GFDQ/article/view/244.