Albeverio, S. A., Ayupov, S. A., & Omirov, B. A. (2006). Cartan Subalgebras, Weight Spaces, and Criterion of Solvability of Finite Dimensional Leibniz Algebras. Revista Matemática Complutense, 19(1), 183-195. https://doi.org/10.5209/rev_REMA.2006.v19.n1.16652