Rossini, M., D’Avola, G., Muratore, M., Malavolta, N., Silveri, F., Bianchi, G., … Adami, S. (2013). Regional differences of vitamin D deficiency in rheumatoid arthritis patients in Italy. Reumatismo, 65(3), 113–120. https://doi.org/10.4081/reumatismo.2013.113