Cohen, C.; Wakeling, J.L.; Mandiwana-Neudani, T.G.; Sande, E.; Dranzoa, C.; Crowe, T.M.; Bowie, R.C.K. (2012). Phylogenetic affinities of evolutionarily enigmatic African galliforms: the Stone partridge Ptilopachus petrosus and Nahan's francolin Francolinus nahani, and support for their sister relationship with New World quails. Ibis. 154 (4): 768—780. doi:10.1111/j.1474-919X.2012.01269.x.
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W. Jardine & P.J. Selby: Illustrations of ornithology. Cz. 4. Edinburgh: W.H. Lizars, 1837, ss. ryc. xvi i tekst.