Seroprevalence of hepatitis B in Nahavand, Islamic Republic of IranA.H.M. Alizadeh, M. Ranjbar, S. Ansari, A. MirArab, S.M. Alavian, K. Mohammad, P. Adibi, GhH. Sadri, F. Keramat, A. Ardalan, M.Arabi, S. Gharekhani, A. Ataei, GhR. Amraei, M. Hosseinzadeh, S. Hatami and M. Zali