Abdel-Aziem, A.; El-Gendy, M. S.; Abdelhamid, A. O. Synthesis and Antimicrobial Activities of pyrido[2,3-d]pyrimidine, Pyridotriazolopyrimidine, Triazolopyrimidine, and pyrido[2,3-d:6,5d’]dipyrimidine Derivatives. Eur. J. Chem. 2012, 3, 455-460.