1. California oil field norm study;Bailey,1995
2. Radiation risk from natural radioactivity in oil and gas production industry;Eid,1996
3. Groundwater;Freeze,1979
4. Godoy, J.M., Miekeley, N., 1998. Radium discharges due to oil off-shore production-case study: Bacia de Campos, Brazil. Proceedings of the International Symposium on Marine Pollution, Monaco, April 1998, IAEA-SM-354/67P, 1998.
5. NORM contamination in the petroleum industry;Gray;Journal of Petroleum Technology,1993