1. Bentonite beds and discontinuity surfaces as correlative tools in the lower to middle Ordovician carbonates of Baltoscandia;Bagnoli,1999
2. Ordovician;Bassett,1992
3. Concentrated and lean oolites: examples from Nubia formation at Aswan, Egypt, and significance of the oolite types in ironstone genesis;Bhattacharyya,1989
4. Basin development in North Wales during the Arenig;Beckley;Geological Journal,1987
5. Nomenclature, stratigraphy, chemical fingerprinting, and areal distribution of some Middle Ordovician K-bentonites in Baltoscandia;Bergström;GFF,1995