Yong Liu, Ming Xiao, Huai-Xing Wang & Xian-Xing Chi. (1970). Ab Initio Study on the Aromaticity of All-Metallic Anion $La^{2-}_4$.
            <i>Journal of Atomic and Molecular Sciences</i>. <i>5</i> (1).
            51-57.
         doi:10.4208/jams.031213.052613a