It was a close relative of Yanornis and together with this and Yixianornis may form a clade.[2] It is sometimes considered to be the same genus as Yanornis (which, described after Songlingornis, would then be merged into that taxon),[3] but this is not universally accepted.[4]
Clarke, Julia A.; Zhou, Zhonghe & Zhang, Fucheng (2006): Insight into the evolution of avian flight from a new clade of Early Cretaceous ornithurines from China and the morphology of Yixianornis grabaui. Journal of Anatomy208 (3):287-308. doi:10.1111/j.1469-7580.2006.00534.xPMID16533313PDF fulltextElectronic Appendix
Gong, Enpu; Hou, Lianhai & Wang, Lixia (2004) Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, China. Acta Geologica Sinica78(1): 1–7.
Hou (1997) Mesozoic Birds of China, Phoenix Valley Provincial Aviary, Taiwan: 153 pp.
Mortimer, Michael (2004): The Theropod Database: Phylogeny of taxa. Retrieved 2013-MAR-02.