1. World Health Organization. (2007). Guidelines for drinking water quality, Vol 1, recommendations, 3rd Ed., WHO, Geneva.
2. Institute of Standards and Industrial Research of Iran. (2007). Potable water the physical and chemical charatcteristics, 5th Ed., The National Iranian Standard in 1053, Tehran, Iran. (In Persian)
3. Imandel, K. (1998). “Ascending trend of nitrate contamination in wells of Tehran west aquifer.” J. Iran Biomedical, 196, 1-4. (In Persian)
4. Lee, S.M., Min, K.D., Woo, N.C., Kin, Y.J., and Ahn, C.H. (2003). “Statistical models for the assessment of nitrate contamination in urban groundwater using GIS.” J. Environmental Geology, 44, 210-221.
5. Almasri, M.N., and Kaluarachchi, J. (2004). “Multi-criteria decision analysis for the optimal management of nitrate contamination of aquifers.” J. Environmental Management, 74(4), 365-381.
6. Prakasa Roa, E. V. S., and Puttanna, K. (2006). “Strategies for combating nitrate pollution.” J. Current Science, 91(10), 1335-1339
7. Rogers, L. L., and Dowla, F. U. (1994). ”Optimization of groundwater remediation using artificial neural networks and parallel solute transport modeling.” J. Water Resources, 30(2), 457-481.
8. Wang, M., and Zheng, C. (1998). “Groundwater management optimization using genetic algorithms and simulated annealing formulation and comparison.” J. Water Resources, 34(3), 519-530.
9. Ramasamy, N., Krishnan, P., Bernard, J.C., and Ritter, W. F. (2003). “Modeling nitrate concentration in groundwater using regression and neural networks.” Department of Food and Resource Economics, University of Delaware, New York.
10. Yesilnacar, M.I., Sahinkaya, E., Naz, M., and Ozkaya, B. (2008).“Neural network prediction of nitrate in groundwater of Harran Plain, Turkey.” J. Environmental Geology, 56, 19-25.
11. Nasseri, M., Tajrishy, M., Nikoo, M.R., and Zaherpour, J. (2011). “ Recognition and spatial mapping of multivariate groundwater quality index using combined fuzzy method.” J. Water and Wastewater, 85, 82-93. (In Persian)
12. Moashrei, S.A., Tabatabaie, S.M., Razaghi, P., Sarani, N., and Eslami Mahdi Abadi, S.H. (2012). “Estimating the groundwater nitrate by using artificial neural network and optimizing it by genetic algorithm.” Proc. Environment and Civil Engineering, Kuala Lumpur, Malaysia, 85-92.
13. Zare Abyaneh, H., Bayat Varkeshi, M., Akhavan, S., and Mohammadi, M. (2011). “Estimation of nitrate in hamedan-bahar plain groundwater using artificial neural network and effect of data resolution on prediction accuracy.” J. Environmetal Studies, 37(58), 129-140.
14. Tapoglou, E., Trichakis, I.C., Dokou, Z., and Karatzas, G.P. (2012). “Groundwater level forecasting using an artificial neural network trained with particle swarm optimization.” Proc. Geophysical Research, Brono-kreisky-platzl, Vienna, Austria, 2405.
15. Kennedy, J., and Eberhart, R. C. (1998). “Particle swarm optimization.” Proc. Neural Network, Piscataway, Perth. Australia, 1942-1948.
16. Fallah Mehdipoor, E. (2008). “Application multipurpose evolutionary optimization method in multi reservoir system operation.” M.S. Thesis, University of Tehran, Iran. (In Persian)
17. Parsopoulos, K.E., and Vrahatis, M.N. (2002). “Recent approaches to global optimization problems through particle swarm optimization.” J. Natural Computing, 1(2-3), 235-306.
18. Tang, Y., and Guan, X. (2007). “Parameter estimation for time-delay chaostic system by particle swarm optimization.” J. Chaos, Solitons and Fractals, 44, 198-207.
19. Redondo, M.F., and Espinosa, C.H. (1999). “Input selection by multilayer feed forward trained networks.” Proc. Neural Netwoks, Washington, DC., 3, 1834-1839.
20. Utans, J., Moody, J., Rehfuss, S., and Siegelmann, H. (1995). “Input variable selection for neural networks: Application to prediction the U.S Business cycle.” Proc. Computational Intelligence for Financial Engineering, New York, 118-122.