Garrity GM, Holt JG (2001). «Taxonomic Outline of the Archaea and Bacteria». En DR Boone and RW Castenholz, eds., ed. Bergey's Manual of Systematic Bacteriology Volume 1: The Archaea and the deeply branching and phototrophic Bacteria (2nd ed. edición). Nueva York: Springer Verlag. pp. 155-166. ISBN978-0-387-98771-2.