1. Alberti, H. (1979): Devonian trilobite stratigraphy. - Spec. Pap. Paleont.,23, 313–324, London.
2. — (1981): Scutellidae (Trilobita) aus dem Unterdevon des Hamar Laghdad (Tafilalt, SE-Marokko) und das Alter der »mud-mounds« (Ober-Zlichovium bis tiefes Dalejum). - Senckenbergiana letaea,62, 193–204, Frankfurt a.M.
3. Allen, J. R. L. (1979): Old Red Sandstone fades in external basins, with particular reference to southern Britain. - Spec. Pap. Palaeont.,23, 65–80, London.
4. Alvarez, L. W., Alvarez, W., Asaro, F. &Michel, H. V. (1980): Extraterrestrial cause for the Cretaceous-Tertiary extinction. - Science,208, 1095–1108.
5. Alvarez, W., Kauffmann, E. G., Surlyk, F., Alvarez, L. W., Asaro, F. &Michel, H. V. (1984): Impact theory of mass extinctions and the invertebrate fossil record. - Science,223, 1135–1141.