Identifying the fundamental units of bacterial diversity: a paradigm shift to incorporate ecology into bacterial systematics.
Koeppel A, Perry EB, Sikorski J, Krizanc D, Warner A, Ward DM, Rooney AP, Brambilla E, Connor N, Ratcliff RM, et al. Proc Natl Acad Sci U S A. 2008 Feb 19; 105(7):2504-9. Epub 2008 Feb 12.