El-Mahdy, K. “Synthesis of Some New Tetracyclic Pyrimidine Derivatives Using Exocyclic α,β-Unsaturated Ketone and Evaluation of Their Antitumor Activities”. JOURNAL OF ADVANCES IN CHEMISTRY, vol. 4, no. 1, Apr. 2008, pp. 311-7, doi:10.24297/jac.v4i1.960.