Baseline hepatitis C virus resistance-associated substitutions present at frequencies lower than 15% may be clinically significant oleh Perales C, Chen Q, Soria ME, Gregori J, Garcia-Cehic D, Nieto-Aponte L, Castells L, Imaz A, Llorens-Revull M, Domingo E, Buti M, Esteban JI, Rodriguez-Frias F, Quer J