“Synthesis of Tetra Dentate N2O2 and Their Complexes With Cu[II), Zn[II), Cd[II) and Hg[II) Ions”. Ibn AL-Haitham Journal For Pure and Applied Sciences, vol. 27, no. 3, Apr. 2017, pp. 393-06, https://jih.uobaghdad.edu.iq/index.php/j/article/view/305.