1. Cohen Y. Jorgensen B.B., Padan E. & Shilo M. (1975) Nature, Lond. 257, 489–492
2. Doolittle, W.F. (1996) In “Evolution of Microbial Life” eds D.M. Roberts et al Cambridge University Press, pp. 1–21
3. Waterbury, J.B., Watson, S.W., Valois, F.W. & Franks D.G. (1986) Can. Bull Fish. Aquat.Sci. 214, 71–120
4. Summers, M.C., Wallis, J.G., Campbell, E.L. & Meeks, J.C. (1995) J. Bact. 177, 6184–6194
5. Scanlan, D.J., Sundaram, S. Newman J., Mann, N.H. & Carr, N.G. (1995) J.Bact. 177, 2250–2553