A. Abdel-Aziem, M. S. El-Gendy, and A. O. Abdelhamid, “Synthesis and antimicrobial activities of pyrido[2,3-d]pyrimidine, pyridotriazolopyrimidine, triazolopyrimidine, and pyrido[2,3-d:6,5d’]dipyrimidine derivatives”, Eur. J. Chem., vol. 3, no. 4, pp. 455–460, Dec. 2012.