Yang, Yi-Sheng, et al. “Solvothermal Synthesis, Characterization and Crystal Structure of a New Supramolecular Compound Composed by 1,10-Phenanthroline Ligand With Bi(III) and Cu(II)”. Asian Journal of Chemistry, vol. 24, no. 11, June 2012, pp. 5368-70, https://asianpubs.org/index.php/ajchem/article/view/9870.