Borri, D. Bosco, D. Civitella, F. Cotecchia, V. Polemio, M. Spizzico, M. Tadolini, T., 1996, Problems and knowledge cases of underground transport networks, Int. Conf. "Planning for self-sustainable development", pp. 117–138, Otranto, 16-18/5/1996,
URL: http://www.cnr.it/prodotto/i/251708

Data from https://intranet.cnr.it/people/