Kroodsma, D., Brewer, D., Christie, D.A. & Bonan, A. (2017) Eurasian Wren (Troglodytes troglodytes) I: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2016). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. Henta den 22. april 2017
mythfolklore.net
Plutarch, Political Precepts xii.806e; Laura Gibb, tr. Aesop's Fable #238; Plutarch's brief account is referenced by Erasmus, Adages iii.7.1, accounting for the hostility of the eagle ("a creature at war with everyone") towards the wren