EMBO J. 2006 Oct 18;25(20):4933-42. doi:10.1038/sj.emboj.7601368

Imbert I, Guillemot JC, Bourhis JM, Bussetta C, Coutard B, Egloff MP, Ferron F, Gorbalenya AE, Canard B.

A second, non-canonical RNA-dependent RNA polymerase in SARS coronavirus.

This enzyme is dependant on Mn2+ and does not require a primer.