Strandberg, A. and Asteling, R. (1998) “Polygyny, hybridisation, double-brooding, a case of site fidelity and time of laying of the Chiffchaff Phylloscopus collybita in southern Sweden”, Ornis Svecica. Lund, Sweden, 8(3), pp. 125–128. doi: 10.34080/os.v8.22951.