S. C.  Kumbharkar, Karadkar, P. B., and Kharul, U. K., ?Enhancement of gas permeation properties of polybenzimidazoles by systematic structure architecture?, Journal of Membrane Science, vol. 286, no. 1-2, pp. 161-169, 2006.

S. C.  Kumbharkar and Kharul, U. K., ?N-substitution of polybenzimidazoles: synthesis and evaluation of physical properties?, European Polymer Journal, vol. 45, no. 12, pp. 3363-3371, 2009.

S. C.  Kumbharkar and Kharul, U. K., ?Investigation of gas permeation properties of systematically modified polybenzimidazoles by N-substitution?, Journal of Membrane Science, vol. 357, no. 1-2, pp. 134-142, 2010.

R. S.  Bhavsar, Kumbharkar, S. C., and Kharul, U. K., ?Investigation of gas permeation properties of film forming polymeric ionic liquids (PILs) based on polybenzimidazoles?, Journal of Membrane Science, vol. 470, pp. 494-503, 2014.