Michelsen, Verner. 2009. “Revision of the Willow Catkin Flies, Genus Egle Robineau-Desvoidy (Diptera: Anthomyiidae), in Europe and Neighbouring Areas”. Zootaxa 2043 (1). Auckland, New Zealand:1–76. https://doi.org/10.11646/zootaxa.2043.1.1.