Robert Kennedy, Pedro C. Gonzales, Edward Dickinson, Hector C. Miranda, Jr, Timothy H. Fisher: A Guide to the Birds of the Philippines, s. 12. Oxford University Press, 2000. ISBN 978-0-19-854669-6. Kirja Googlen teoshaussa (viitattu 8.8.2020). (englanniksi)
BirdLife International: Kittacincla nigraIUCN Red List of Threatened Species. Version 2020-2. 2016. International Union for Conservation of Nature, IUCN, Iucnredlist.org. Viitattu 8.8.2020. (englanniksi)