3[1]Chemin I,Zoulim F,Merle P,et al.High incidence of hepatitis B infections among chronic hepatitis cases of unknown aetiology[J].Hepatol,2001,34:447.
4[3]Brechot C,Thiers V,Kremsdorf D,et al.Persistent hepatitis B virus infection in subjects without hepatitis B surface antigen:clinically significant or purely"occult"[J].Hepatolohy,2001,34:194.
5[4]Chan HL,Tsang S,Leung N,et al.Occult HBV infection in cryptogenic liver cirrhosis in an area with high prevalence of HBV infection[J].Am J Gastroenterol,2002,97:1211.
6[6]Cacciola I,Pollicino T,Squadrito G,et al.Occult hepatitis B virus infection in patients with chronic hepatitis C liver disease[J].N Engl J Med,1999,341:22.
7[7]Su Q,Wang SF,Chang TE,et al.Circulating hepatitis B virus nucleic acids in chronic infection:representation of differently polyadenylated viral transcripts during progression to nonreplicative stages[J].Clin Cancer Res,2001,7:2005.
8[8]Conjeevaram HS,Lok AS.Occult hepatitis B virus infection:a hidden menace[J].Hepatology,2001,34:204.