Sparlin, D.D., Hagen, R.W. Jr. (1984) Controlling water in producing operations, Part 1- Where it comes from and the problems it causes, World Oil J..
 Moradi Araghi, A. (2005) A review of thermally stable gels for fluid diversion in petroleum production, J. of Petroleum Science and Engineering, Vol. 26, pp.1-10.
 Nasr-El-Din, H.A., Taylor, K.C. (2005) Evaluation of sodium silicate/urea gels used forwater shut-off treatments, Journal of Petroleum Science and Engineering, Vol. 48, pp.141-160.
 Seright, R.S. (2001) A Strategy for attacking excess water production, SPE Permian Basin Oil and Gas Recovery Conference, Midland, Texas, Paper SPE 70067.
 Nasr-El-Din, H.A., Bitar, G., Bou-Khamsin, F.I., Al-mulhim, A., Hsu, J. (2000) Field application of gelling polymers in Saudi Arabia, SPE/DOE Improved Oil Recovery Symposium, Tulsa,Oklahama, Paper SPE 39615.
 Stavland, A., Andersen, K.I., Sandøy, B. (2006) How to apply a blocking gel system for bullhead selective water shutoff: from laboratory to field, SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Oklahoma, Paper SPE 99729.
 Seright, R.S. (1997) Improved methods for Water Shutoff, Semiannual Report (DOE/PC/91008-1), Contract No. DE-AC22-94PC91008, U.S. DOE, 82-95.
 Willhite, G. P. and Pancake, R. E. (2004) Controlling water production using polymer gel system, SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Oklahoma, Paper SPE 89464.
 Simjoo, M., Vafaie-Seftie, M., Dadvand-Koohi, A., Hasheminasab, R., Sajjadian, V.A. (2007) Polyacrylamide polymer gel as water shut-off system: Preparation and investigation of physical and chemical properties in one of the Iranian oil reservoirs conditions, Iran J Chem and Chem Eng, Vol. 26, pp.99-108.
 Willhite, G.P., Pancake, R.E. (2008) Controlling water production using polymer gel system, SPE Res Eval & Eng, pp. 454-465.
 Eoff, L., Dalrymple, D., Everett, D., Vasquez, J. (2006) Worldwide field application of a polymeric gel system for conformance applications, SPE Prod & Oper, Vol. 22, pp. 231-235.
 Al-Muntasheri, G.A., Nasr-El-Din, H.A., Al-Noaimi, K.R., Zitha, P.L.J. (2007) A study of polyacrylamide-based gels crosslinked with polyethyleneimine, International Symposium on Oilfield Chemistry, Houston, Texas, Paper SPE 105925.
 Chauveteau, G., Tabary, R., Renard, M., Omari, A. (1999) Controlling in-situ gelation of polyacrylamides by zirconium for water shutoff, SPE International Symposium on Oilfield Chemistry, Houston, Texas, Paper SPE 50752.
 Albonico, P., Burrafato, G., Lockhart, T.P. (1992) Polyacrylamide gels formed with Cr3+
ion and Cr(acetate)3: thermodynamically and kinetically controlled cross-linking reactions, J Pet Sci and Eng
, Part A, Vol. 30, pp. 1071–1075.
 Broseta, D., Marquer, O., Blin, N., Zaitoun, N. (2000) Rheological screening of low-molecular-weight polyacrylamide/chromium (III) acetate water shutoff gels, SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Oklahoma, Paper SPE 59319.
 Romero-Zeron, L.B., Manalo, F., Kantzas, A. (2004) Characterization of cross-linked gel kinetics and gel strength using NMR, SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, Paper SPE 86548.
 Aalaie, J., Vasheghani-Farahani, E., Semsarzadeh, M.A., Rahmatpour, A. (2008) Gelation and swelling behavior of semi-interpenetrating polymer network hydrogels based on polyacrylamide and poly(vinyl alcohol), J Macro Sci, Part B: Physics, Vol. 47, pp. 1017–1027.
 Aalaie, J., Vasheghani-Farahani, E., Rahmatpour, A., Semsarzadeh, M.A. (2008) Effect of Montmorillonite on Gelation and Swelling Behavior of Sulfonated Polyacrylamide Nanocomposite Hydrogels in Electrolyte Solutions, European Polymer Journal, Vol. 44, pp. 2024–2031.
 Gao, D., Heimann, R.B. (1993) Structure and Mechanical Properties of Super-absorbent Poly(acrylamide)-Montmorillonite Composite Hydrogles, Polym. Gels. Networks, Vol. 1, pp. 225-246.
 Sydansk, R. (1987) Conformance improvement in a subterranean hydrocarbon-bearing formation using a polymer gel, US Patent, No. 4683949.
 Zolfaghari, A., Katbab, A.A., Nabavizadeh, J., Yousefzadeh Tabasi, R., Hossein Nejad, M. (2006) Preparation and Characterization of Nanocomposite Hydrogels Based on Polyacrylamide for Enhanced Oil Recovery Applications, Journal of Applied Polymer Science, Vol. 100, pp. 2096–2103.
 Engineering Statistics Handbook, (2003) National Institute of Standards and Technology and the International SEMATECH.
 Baghban Salehi, M., Vafaie Sefti, M., Mousavi Moghadam, A., Dadvand Koohi, A. (2012) Study of Salinity and pH Effect on Gelation Time of Polymer Gel Using in Water Shut-off with Central Composite Design Method, Journal of Macromolecular Science, Part B: Physics, Vol. 51(3), pp. 438-451, 2012.