Haq & Aubry 1980. Early Caenozoic calcareous nannoplankton biostratigraphy and palaeobiogeography of North Africa and the Middle East and trans-Tethyan correlations. Salem, M.J.; Busrewil, M.T.[Eds]. The geology of Libya. Volume 1., Academic Press, London, New York etc., 1980: 271-304. Chapter pagination: 271-304