Johansson et al.: Phylogenetic relationships within Passerida (Aves: Passeriformes): A review and a new molecular phylogeny based on three nuclear intron markers In: Molecular Phylogenetics and Evolution. Volume 48, Issue 3, September 2008, Pages 858—876 doi:10.1016/j.ympev.2008.05.029PMID 18619860
Johansson et al.: Phylogenetic relationships within Passerida (Aves: Passeriformes): A review and a new molecular phylogeny based on three nuclear intron markers In: Molecular Phylogenetics and Evolution. Volume 48, Issue 3, September 2008, Pages 858—876 doi:10.1016/j.ympev.2008.05.029PMID 18619860