1. Bancroft, B.B. 1933. Correlation tables of the Stages Costonian–Onnian in England and Wales.Privately Printed at Nibley House. Blakeney, Gloucestershire.
2. Atmospheric Carbon Dioxide Levels Over Phanerozoic Time
3. Deep-sea carbonates: Reading the carbon-isotope signal;Berger;Geologische Rundschau,1986
4. Brenchley P. J. (1989) in Mass Extinctions: Processes and Evidence, The late Ordovician extinction, ed Donovan S. K. (Columbia University Press, New York), pp 104–132.
5. Ecological associations in a regressive sequence: the latest Ordovician of the Oslo-Asker district, Norway;Brenchley;Palaeontology,1982