ABUNADAA, N.M., A.K.K. EL-LOUH, and I.S. AL-ZAEEM. 2010. “Synthesis and Characterization of Thioxopyridine, Pyrazolopyridine and Pyridopyrazolotriazine Derivatives”. Asian Journal of Chemistry 19 (6):4575-85. https://asianpubs.org/index.php/ajchem/article/view/19986.