1. Vidal, G. Publ. Inst. Mineral. Palaeont. Quat. Geol Univ. Lund 219, 1–22 (1979).
2. Vidal, G. Fossils Strata 9, 1–57 (1976).
3. Knoll, A. H. in Paleobotany, Paleoecology, and Evolution Vol. 1 (ed. Niklas, K. J.) 17–54 (Praeger, New York, 1981).
4. Vidal, G. Norges Geol. Unders. 362, 1–53 (1981).
5. Timofeev, B. V. Mem. 129, 1???350 (V.N.I.G.R.I., Leningrad, (1959);