| BONI C. (1992) – Karst hydrogeology in Central Italy – Int. Contr. To Hydrogeology, 13 Karst Commission, Verlag Heinze, Hannover. |
| BONI C. (1992) – Karst hydrogeology in Central Italy – Int. Contr. To Hydrogeology, 13 Karst Commission, Verlag Heinze, Hannover. |