Johansson, Ulf S.; Fjeldså, Jon; Bowie, Rauri C. K. (2008-09-01). "Phylogenetic relationships within Passerida (Aves: Passeriformes): A review and a new molecular phylogeny based on three nuclear intron markers". Molecular Phylogenetics and Evolution. 48 (3): 858–876. doi:10.1016/j.ympev.2008.05.029. PMID18619860.
Johansson, Ulf S.; Fjeldså, Jon; Bowie, Rauri C. K. (2008-09-01). "Phylogenetic relationships within Passerida (Aves: Passeriformes): A review and a new molecular phylogeny based on three nuclear intron markers". Molecular Phylogenetics and Evolution. 48 (3): 858–876. doi:10.1016/j.ympev.2008.05.029. PMID18619860.