1. Aly, A.I.M., Nada,A., Awad, M., Hamza,M.S. and Salman,A.B. 1989. Isotope Hydrological Investigation in Qattara Depression Egypt, Isotopenpraxis, 25, (1), 22?24.
2. Atwa, S.M., 1979. Hydrology and Hydrogeochemistry of the Northwestern Coast of Egypt. PhD Dissertation, Faculty of Science, University of Alexandria, Alexandria, Egypt.
3. Craig, H. 1961. Standard for Reporting Concentration of Deuterium and Oxygen-18 in Natural Waters. Science, 133, 1833.
4. El Shamy, I. 1968. The Geology and Soil Resources in El-Dabaa Area, Western Mediterranean Coastal Zone. M.Sc. Thesis in Geology, Faculty of Science, Cairo University, Cairo, Egypt.
5. Epstein, S., and Mayeda,T. 1953. Variation of 18O Content of Waters from Natural Sources. Geochim Cosmoshim-Acta, 4, 213.