Reference

Jochen Martens, Martin Päckert, Alexander A. Nazarenko, Olga Valchuk, Noritomo Kawaji (1998): Comparative bioacoustics of territorial song in the Goldcrest (Regulus regulus) and its implications for the intrageneric phylogeny of the genus Regulus (Aves: Passeriformes: Regulidae) – Zoologische Abhandlungen - Staatliches Museum für Tierkunde Dresden – 50: 99 - 128.