Sonntag, C., Muennich, K. O., Junghans, C., Klitzsch, E., Thorweihe, U., Weistroffer, K., … & Swailem, F. M. (1979). Palaeoclimatic information from deuterium and oxygen-18 in carbon-14-dated north Saharian groundwaters. Groundwater formation in the past. In Isotope hydrology 1978.