NYSTRÖM, K. G. K. An examination of perched Willow Warblers Phylloscopus trochilus singing on one leg. Ornis Svecica, Lund, Sweden, v. 32, p. 38–46, 2022. DOI: 10.34080/os.v32.22447. Disponível em: https://journals.lub.lu.se/os/article/view/22447. Acesso em: 15 aug. 2022.