Balch, W.E., Fox, G.E., Magrum, L.J., Woses, C.R., and Wolfe, R.S. "Methanogens: reevaluation of a unique biological group." Microbiol. Rev. (1979) 43:260-296. [No abstract available.]

Euzeby, J.P., and Tindall, B.J. "Nomenclatural type of orders: corrections necessary according to Rules 15 and 21a of the Bacteriological Code (1990 Revision), and designation of appropriate nomenclatural types of classes and subclasses. Request for an Opinion." Int. J. Syst. Evol. Microbiol. (2001) 51(2):725-727.

Judicial Commision of the International Committee on Systematics of Prokaryotes: "The nomenclatural types of the orders Acholeplasmatales, Halanaerobiales, Halobacteriales, Methanobacteriales, Methanococcales, Methanomicrobiales, Planctomycetales, Prochlorales, Sulfolobales, Thermococcales, Thermoproteales and Verrucomicrobiales are the genera Acholeplasma, Halanaerobium, Halobacterium, Methanobacterium, Methanococcus, Methanomicrobium, Planctomyces, Prochloron, Sulfolobus, Thermococcus, Thermoproteus and Verrucomicrobium, respectively. Opinion 79." Int. J. Syst. Evol. Microbiol. (2005) 55:517-518.