T. T. Khidr, E. M. S. Azzam, S. Mutwaa and A. M. A. Omar, “Study of Some Anionic Surfactants as Pour Point Depressant Additives for Wax Gas Oil,” Industrial Lubrication and Tribology, Vol. 59, No. 2, 2007. pp. 64-68.
 T. T. Khidr and A. M. A. Omar, “Anionic/Nonionic Mixture of Surfactants for Pour Point Depression of Gas Oil Egyptian,” Journal of Petroleum, Vol. 12, 2003, pp. 21-26.
 T. T. Khidr, D. Ismail and A. M. A. Omar, “Improving the Flow Properties of n-Paraffin Gas Oil by Cationic and Non-Ionic Surfactants,” Journal of Faculty of Education, Vol. 25, 2000, pp. 121-135.
 C. Kaidas, M. Makowska and M. Gradkowski, “Influence of Temperature on Tribochemical Reactions of n-Hexadecane,” 2nd World Tribology Congress, 3-7 September 2001, p. 225.
 N. Elmehbad, “Development Antioxidants Synthesized by Phase Transfer Catalysts for Lubricating Oil,” Biotech Conference, Expo, 12-16 May 2013
 A. M. A. Omar, “Micellization and Adsorption of Anionic/Nonionic Polymer Surfactants for Metal Working Fluid at Different Interfaces,” Industrial Lubrication and Tribology, Vol. 56, No. 3, 2004, pp. 171-176.
 T. R. Marquat, G. B. Dellow and E. R. Freitaus, Analytical Chemistry, Vol. 40, No. 11, 1968, p. 1633.
 A. M. A. Omar, Journal of Petroleum Science and Technology, Vol. 19, No. 7-8, 2001, pp. 11-21.
 M. Y. El Kady, A. K. El Morsi, N. Tantawi, A. Z. El Tabei and A. M. A. Omar, “A New Trend for Preparing Polymeric Calcium Sulphonates for Metal q Working Fluids,” Journal of Annals of University, Dunarea De Jos of Galati, Tribology, Fascice, Romania, Vol. 11, 2006.
 S. H. Hasting, B. H. Johnson, H. E. lumpkin and R. B. Wiliam, “Symposium on Composition of Petroleum Oils Determination,” American Society for Testing Materials, 1958.