↑ See for a detailed geologic timescale Gradstein et al. (2004)
Văn liệu
Cossmann, M. & Pelat, E. (1907): Le Barrémien supérieur à faciès Urgonien de Brouzet-lès-Alais (Gard). Mémoires de la Société Géologique de France, Paléontologie 15(37): 5-42. (tiếng Pháp)
Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; (2004): A Geologic Time Scale 2004, Cambridge University Press.
Guzhikov, A.Yu. & Baraboshkin, E.J. (2006): Assessment of diachronism of biostratigraphic boundaries by magnetochronological calibration of zonal scales for the Lower Cretaceous of the Tethyan and Boreal belts. Doklady Earth Sciences 409(6): 843-846.doi:10.1134/S1028334X06060018
