In search of a bacterial species definition. 1997.
D020561:Alphaproteobacteria / Q000145:classification*; D020369:Bradyrhizobium / Q000145:classification*; D049673:History, 20th Century; D010802:Phylogeny; D012241:Rhodopseudomonas / Q000145:classification*; D013045:Species Specificity