Gad, A.A., et al. “Cu(II), Ni(II), Co(II), and Mn(II) Complexes of Arylidenes-2-Amino-4-Methyl Pyrimidine”. Asian Journal of Chemistry, vol. 3, no. 1, Mar. 2010, pp. 99-104, https://asianpubs.org/index.php/ajchem/article/view/25195.