Butovskii, M. V., Tok, O. L., Bezugly, V., Wagner, F. R., & Kempe, R. (2011). Molecular Lanthanoid–Transition-Metal Cluster through CH Bond Activation by Polar Metal–Metal Bonds. Angewandte Chemie - International Edition, 50(33), 7695-7698. doi:10.1002/anie.201102363.