Reference

Peter E. Isaacson, Jindrich Hladil, Jian-Wie Shen, Jiri Kalvoda, George Grader (1999): Late Devonian (Famennian) Glaciation in South America and Marine Offlap on other Continents – Abhandlungen der Geologischen Bundesanstalt in Wien – 54: 239 - 257.