1. Bäumle R (2004) Groundwater investigations of the Oshivelo artesian aquifer: isotope sampling campaign for the investigation of the recharge, groundwater quality and flow mechanisms. Report, IAEA/DWA, Windhoek, Namibia
2. Bäumle R, Himmelsbach T, Bufler R (2001) Conceptual hydrogeological models to assess the groundwater resources of the heterogeneous fractured aquifers at Tsumeb (northern Namibia). In: Seiler K-P, Wohnlich S (eds) Proc. of the XXXI IAH Congress: new approaches characterizing groundwater flow, Munich, 10–14 September 2001. Balkema, Lisse, The Netherlands, pp 245–249
3. Berner U, Streif H (2004) Klimafakten: der Rückblick—ein Schlüssel für die Zukunft [Facts about climate: retrospect—a key to the future]. Bundesanstalt für Geowissenschaften und Rohstoffe, Hanover, Germany
4. Bittner ACW (1998) Drilling of a deep freshwater borehole in the Eenhana area applying the EDL-Technique. Ministry of Agriculture Ward, Dept. of Water Affairs, Windhoek, Namibia, 12 pp
5. Bittner ACW (2008) Drilling and testing of 4 exploration wells along M110 between Mpungu and Elundu. Bittner Water Consult, Windhoek, Namibia, 41 pp