Benton, M.J. (ed). (1993). The Fossil Record 2. Chapman & Hall, London, 845 pp.
Benton, M.J. (ed). (1993). The Fossil Record 2. Chapman & Hall, London, 845 pp.
Brands, S. J. (compiler). (1989-2005). Systema Naturae 2000. Amsterdam, The Netherlands (2006 version). Originally available online at http://sn2000.taxonomy.nl/; for current information, refer http://taxonomicon.taxonomy.nl/ProjectDescription.aspx .