Castelluccio, M., G. Giannella, C. Lucchetti, M. Moroni, and P. Tuccimei. “Classification of Radon Hazard in Urban Planning Focused to Risk Management”. Italian Journal of Engineering Geology and Environment, no. 2, Dec. 2012, pp. 5-16, doi:10.4408/IJEGE.2012-02.O-01.