Literature
  • Ouellet, van Zyll de Jong 1990
  • Feather identification by means of keratin protein electrophoresis. 20th Meeting Bird Strike Committee Europe (Helsinki). Working Paper 8: 53-71.
  • Laybourne 1994
  • Feather in amber is earliest New World fossil of Picidae. Wilson Bulletin 106: 18-25.
  • , 1995
  • Five Kingdoms. CD-ROM, edition 1.0, published by ETI, Amsterdam.
  • , 1988
  • Five Kingdoms. W. H. Freeman and Company, New York. 376 pp.