Holmgren, Noél M A, and Henri Engström. “Stopover Behaviour of Spring Migrating Wood Warblers Phylloscopus Sibilatrix on the Island of Capri, Italy”. Ornis Svecica, vol. 16, no. 1–2, Apr. 2006, pp. 34-41, doi:10.34080/os.v16.22721.