Jackson, Jerome A., Henri R. Ouellet, & Bette J. Jackson (2002): Hairy Woodpecker (Picoides villosus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online 2009-3-20 DOI:10.2173/bna.702 (registration required)
Weibel, Amy C. & Moore, William S. (2005): Plumage convergence in Picoides woodpeckers based on a molecular phylogeny, with emphasis on convergence in downy and hairy woodpeckers. Condor 107(4): 797–809. DOI:10.1650/7858.1 (HTML abstract)
Moore, William S.; Weibel, Amy C. & Agius, Andrea (2006): Mitochondrial DNA phylogeny of the woodpecker genus Veniliornis (Picidae, Picinae) and related genera implies convergent evolution of plumage patterns. Biol. J. Linn. Soc. 87: 611–624. PDF fulltext [Архівовано 29 вересня 2011 у Wayback Machine.]
Moore, William S.; Weibel, Amy C. & Agius, Andrea (2006): Mitochondrial DNA phylogeny of the woodpecker genus Veniliornis (Picidae, Picinae) and related genera implies convergent evolution of plumage patterns. Biol. J. Linn. Soc. 87: 611–624. PDF fulltext [Архівовано 29 вересня 2011 у Wayback Machine.]