Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood (2015) The eBird/Clements checklist of birds of the world: Version 2015 http://www.birds.cornell.edu/clementschecklist/download, läst 2015-08-11
BirdLife International and NatureServe (2014) Bird Species Distribution Maps of the World. 2014. Lullula arborea The IUCN Red List of Threatened Species. Version 2015-3