Grenmyr, Urban. “Sex Differences in Recovery Pattern and Migratory Direction of Goldcrest Regulus Regulus Ringed in Northern Europe During Autumn Migration”. Ornis Svecica 7, no. 2 (April 1, 1997): 81–90. Accessed July 6, 2022. https://journals.lub.lu.se/os/article/view/22972.