Radon exhalation rate in south-east Sicily building materials D. Morelli, R. Catalano, R. Filincieri, G. Immé and G. Mangano Eur. Phys. J. Special Topics, 224 4 (2015) 605-610 Published online: 10 June 2015 DOI: 10.1140/epjst/e2015-02394-x