Gibbs et al. 2000. Phylogenetic analysis of some large double-stranded RNA replicons from plants suggests they evolved from a defective single-stranded RNA virus. Journal of General Virology 81: 227–233.                                   jgv.sgmjournals.org/content/journal/jgv/10.1099/0022-1317-81-1-227?crawler=true&mimetype=application/pdf