@article{MT_2012_15_2_a8,
     author = {Yu. G. Nikonorov and M. S. Chebarykov},
     title = {The {Ricci} operator of completely  solvable metric {Lie} algebras},
     journal = {Matemati\v{c}eskie trudy},
     pages = {146--158},
     publisher = {mathdoc},
     volume = {15},
     number = {2},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_2012_15_2_a8/}
}