Davydov, V. I., Korn, D. & Schmitz, M.D. 2012. Chapter 23 – The Carboniferous Period. Teoksessa: Gradstein, F.M., Ogg., J.G., Schmitz, M.D. & Ogg, G.M. (toim.): The Geologic Time Scale 2012, Elsevier, s. 603–651.
