Reference

Daniel R. Gustafsson (2023): Putting the cart before the horse: taxonomy of the species of Philopterus (Phthiraptera: Ischnocera: Philopteridae) of the goldcrest, Regulus regulus (Linnaeus, 1758) (Aves: Passeriformes: Regulidae) – Bonn zoological Bulletin - früher Bonner Zoologische Beiträge. – 72: 85 - 104.