Marova, Irina, Daria Shipilina, Vjatcheslav Fedorovk, Valery Alekseev, and Vladimir Ivanitskii. “Interaction Between Common and Siberian Chiffchaff in a Contact Zone”. Ornis Fennica 94, no. 2 (July 1, 2017): 66–81. Accessed February 16, 2025. https://ornisfennica.journal.fi/article/view/133913.