Kopij, Grzegorz. “Territoriality in the Willow Warbler Phylloscopus Trochilus in Its Winter Quarter in Lesotho”. Ornis Svecica 19, no. 1 (January 1, 2009): 50–54. Accessed April 26, 2024. https://journals.lub.lu.se/os/article/view/22658.