BATTISTUZZI, F.U.; HEDGES, S.B. (2009). A major clade of prokaryotes with ancient adaptations to life on land. Molecular Biology Evolution 26 (2): 335–43. doi:10.1093/molbev/msn247
BERN, M.; GOLDBERG, D. (2005). Automatic selection of representative proteins for bacterial phylogeny. BMC Evolutionary Biology 5 (1): 34. doi:10.1186/1471-2148-5-34
CAVALIER-SMITH, T. (2006). Rooting the tree of life by transition analyses. Biology Direct 1: 19. doi:10.1186/1745-6150-1-19