Egypt NG 35 NW, Sakhret El-Ámud : Atlas for ground water 1:500,000 : Bouguer gravity anomaly map / authorship General Petroleum Company ; conception of the series by G. Pöhlmann, TFH Berlin ; compilation and design by M. Deetz ; map production by M. Deetz, V. Zirn, TFH Berlin / Cairo : General Petroleum Company , 1987