Assiddiqi, Zulqarnain, Sebastianus van Balen, and Nigel J. Collar. 2020. “Mystery Flycatchers in Sumatra - Rück’s Blue-Flycatcher or White-Tailed Flycatcher?”. KUKILA 23 (1), 19-26. http://kukila.org/index.php/KKL/article/view/613.