References
- Fahræus , L. E. 1966 . Lower Viruan (Middle Ordovician) conodonts from the Gullhögen quarry, southern central Sweden . Sveriges Geol. Unders , : 1 – 40 . Ser. C. No. 610, Pls. I—IV
- Lindström , M. 1964 . Conodonts , 1 – 196 . Amsterdam : Elsevier Publishing Co .