Hogstad, Olav. “No Effect of Heavy Metal Content on the External Morphology of First-Year Wintering Willow Tits Poecile Montanus”. Ornis Norvegica 34 (November 21, 2011): 19–23. Accessed April 26, 2024. https://boap.uib.no/index.php/ornis/article/view/217.