Al-Khafaji, Yahya F., Mohammed R. Al-Lami, Ahmed S. Abbas, Ameer Al-Ameri, and Ahmed Falah Albo Mousa. 2017. “Synthesis and Characterization of Niobium and Tantalum Complexes With Bidentate Ligand and Its Use in Ring Opening Polymerization of E-Caprolactone”. Asian Journal of Chemistry 30 (2):460-62. https://doi.org/10.14233/ajchem.2018.21144.