Struck, Torsten H and Paul, Christiane and Hill, Natascha and Hartmann, Stefanie and Hösel, Christoph and Kube, Michael and Lieb, Bernhard and Meyer, Achim and Tiedemann, Ralph and Purschke, Günter and others (2011). “Phylogenomic analyses unravel annelid evolution”. Nature471 (7336): 95-98. doi:10.1038/nature09864.