Literature
- Brom, T. G. 1986. Microscopic identification of feathers and feather fragments of Palearctic birds. Bijdragen tot de dierkunde 56 (2): 181-204.
- Brom, T. G. 1990. Villi and te phyly of Wetmore's order Piciformes (Aves). Zoological Journal of the Linnean Society 98: 63-72.
- Brom, T. G. 1991a. The diagnostic and phylogenetic significance of feather structures. Published thesis, University of Amsterdam.
- Dunning, J. B. Jr. (ed.). 1993. CRC Handbook of Avian Body Masses. CRC Press, Boca Raton, Florida. 371 pp.