Silverin, Bengt, and John Wingfield. 2001. “The Adrenocortical Responses to Stress in Breeding Male Chaffinches Fringilla Coelebs and Bramblings F. Montifringilia in Sweden”. Ornis Svecica 11 (4). Lund, Sweden:223-34. https://doi.org/10.34080/os.v11.22848.