M.A, Firyal., and Assel K. M. “Synthesis of Biopolymers by Condensed Histidine Imide Derivatives With Some Acid Anhydride and Their Crosslink With Acrylonitrite”. Journal of Petroleum Research and Studies 5, no. 1 (June 1, 2014): 27-41. Accessed May 5, 2025. https://www.jprs.gov.iq/index.php/jprs/article/view/107.