1. Department of Mathematics and Computer Science, University of Calabria, Arcavacata, 87036 – Rende (CS), Italy
2. Consiglio Nazionale delle Ricerche, Istituto di Ricerca per la Protezione Idrogeologica, 87036 – Rende (CS), Italy
3. Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata, 87036 – Rende (CS), Italy