Mohammed, Khaled M., and Duraid A. Al-Dulaimi. 2017. “Synthesis and Characterization of Heterocyclic Seven Membered Rings from 2,3-Pyridine Caroboxylic Anhydride”. Ibn AL-Haitham Journal For Pure and Applied Sciences 29 (2): 421-36. https://jih.uobaghdad.edu.iq/index.php/j/article/view/139.