Wang Guoyi Zhu, Peng. “Four Novel Screw-Like Tris(1,10-Phenanthroline) Ruthenium(II) Bishexafluorophosphate Derivatives”. Asian Journal of Chemistry, vol. 11, no. 4, Mar. 2010, pp. 1514-6, https://asianpubs.org/index.php/ajchem/article/view/23521.