"The Coccinellidae (Coleoptera) of America North of Mexico", Robert D. Gordon. 1985. Journal of the New York Entomological Society, Vol. 93, No. 1.
Gordon, Robert D. (1985). "The Coccinellidae (Coleoptera) of America North of Mexico". Journal of the New York Entomological Society, vol. 93, no. 1, 1–912.
Further reading
Arnett, R.H. Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). (2002). American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press LLC, Boca Raton, FL.
Arnett, Ross H. (2000). American Insects: A Handbook of the Insects of America North of Mexico. CRC Press.
Richard E. White. (1983). Peterson Field Guides: Beetles. Houghton Mifflin Company.