^"Axion Report". Integrated Taxonomic Information System. Retrieved 12 February 2018.
^"Axion Overview". Encyclopedia of Life. Retrieved 12 February 2018.
Further reading
Arnett, R. H. Jr.; Thomas, M. C.; Skelley, P. E.; Frank, J. H., eds. (21 June 2002). American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press.
Arnett, Ross H. (30 July 2000). American Insects: A Handbook of the Insects of America North of Mexico. CRC Press. ISBN978-0-8493-0212-1.
White, Richard E. (1983). Peterson Field Guides: Beetles. Houghton Mifflin.
Gordon, Robert D. (1985). "The Coccinellidae (Coleoptera) of America North of Mexico". Journal of the New York Entomological Society. 93 (1).