Moyle, R. G. (2004). "Phylogenetics of barbets (Aves: Piciformes) based on nuclear and mitochondrial DNA sequence data". Molecular Phylogenetics and Evolution. 30 (1): 187–200. doi:10.1016/S1055-7903(03)00179-9. PMID15022769.
hbw.com
Short, L. L.; Horne, J. F. M.; Kirwan, G. M. (2014). "Black-browed Barbet Psilopogon ortii". In del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D. A.; de Juana, E. (eds.). Handbook of the Birds of the World and BirdLife International Illustrated Checklist of the Birds of the World. Vol. 7: Jacamars to Woodpeckers. Barcelona, Spain and Cambridge, UK: Lynx Edicions and BirdLife International.
Moyle, R. G. (2004). "Phylogenetics of barbets (Aves: Piciformes) based on nuclear and mitochondrial DNA sequence data". Molecular Phylogenetics and Evolution. 30 (1): 187–200. doi:10.1016/S1055-7903(03)00179-9. PMID15022769.