1. Geophysics Department; Stanford University; Stanford California USA
2. Schlumberger Doll Research; Cambridge Massachusetts USA
3. Schlumberger Dhahran Carbonate Research; Dhahran Saudi Arabia
4. Schlumberger Water Services; Tucson Arizona USA
5. Nebraska Water Science Center; U.S. Geological Survey; Lincoln Nebraska USA
6. Office of Groundwater-Branch of Geophysics; U.S. Geological Survey; Troy New York USA