Abnormal uroporphyrin levels in chronic hepatitis C virus infection - Martinelli, Ana de Lourdes Candolo; Villanova, Marcia Guimarães; Roselino, Ana Maria Ferreira; Figueiredo, José Fernando de Castro; Passos, Afonso Dinis Costa; Covas, Dimas Tadeu; Zucoloto, Sérgio (Journal of Clinical Gastroenterology, 1999)