Sun exposure questionnaire predicts circulating 25-hydroxyvitamin D concentrations in Caucasian hospital workers in southern Italy - Hanwell, H.E.C.; Vieth, R.; Cole, D.E.C.; Scillitani, A.; Modoni, S.; Frusciante, V.; Ritrovato, G.; Chiodini, I.; Minisola, S.; Carnevale, V. (Journal of Steroid Biochemistry & Molecular Biology, 2010)