1. ALBANESI, G. L. , ORTEGA, G. and ZEBALLO, F. J. 2008. Faunas de conodontes y graptolitos del Paleozoico inferior en la Cordillera Oriental Argentina. Relatorio XVII Congreso Geológico Argentino, Jujuy, 98-118.
2. The Scandinavian Alum Shales;ANDERSSON;Sveriges Geologiska Undersökning,1985
3. The Ordovician basin in the Puna of NW Argentina and N Chile: geodynamic evolution from back-arc to foreland basin;BAHLBURG;Geotektonische Forschungen,1990
4. The proposed Cambrian-Ordovician global boundary stratotype and point (GSSP) in western Newfoundland, Canada;BARNES;Geological Magazine,1988
5. The Geology of the Regions adjacent to Preservation and Chalky Inlets, Fjordland, New Zealand. Part 4. Stratigraphy and Palaeontology of the fossiliferous Ordovician rocks;BENSON;Transactions of the Royal Society of New Zealand,1935