Waldenström, Jonas, and Ulf Ottosson. “The Accuracy of Field Sex Determination in the Common Whitethroat Sylvia C. Communis”.
Ornis Svecica
10, no. 2 (April 1, 2000): 67–70. Accessed May 11, 2025. https://journals.lub.lu.se/os/article/view/20574.