3Tong SP,Li JS.Vitritaski L.et al.Active hepatitis B virus replication in the presence of anti HBe is associated with viral variants containg an inactive pre-C region.Virotogy,1990;176:596.
4Omata M.Ehata T.Yokosuka O.et al.Mutations in the precore region of hepatitis B virus DNA in patients with fulminant and severe hepatitis.N Eng J Med,1991;324:1699.
