TY - RPRT TI - Hepadnavirus envelope proteins regulate covalently closed circular DNA amplification. AU - J Summers AU - P M Smith AU - A L Horwich PY - 1990 DO - 10.1128/jvi.64.6.2819-2824.1990 UR - https://pubmed.ncbi.nlm.nih.gov/2335817/ ID - 2335817 ER -