Nomenclature, stratigraphy, chemical fingerprinting and areal distribution of some Middle Ordovician K-Benonites in Baltoscandia.
Reference:
Bergstrжm,S.M. et al. (1995)
Nomenclature, stratigraphy, chemical fingerprinting and areal distribution of some Middle Ordovician K-Benonites in Baltoscandia. GFF,Geologiska fжreningens i Stockholm fжrhandlingar
Vol. 117 # 1 P. 1- 13