2 citations to https://www.mathnet.ru/rus/mt245

1. Boucetta M., Lebzioui H., “on Flat Pseudo-Euclidean Nilpotent Lie Algebras”, J. Algebra, 537 (2019), 459–477          
2. Nikonorov Yu.G., “Negative Eigenvalues of the Ricci Operator of Solvable Metric Lie Algebras”, Geod. Dedic., 170:1 (2014), 119–133