@article{10_1007_s10587_015_0159_4,
     author = {Arias-Marco, Teresa and Kowalski, Old\v{r}ich},
     title = {Classification of $4$-dimensional homogeneous weakly {Einstein} manifolds},
     journal = {Czechoslovak Mathematical Journal},
     pages = {21--59},
     publisher = {mathdoc},
     volume = {65},
     number = {1},
     year = {2015},
     doi = {10.1007/s10587-015-0159-4},
     mrnumber = {3336024},
     zbl = {06433720},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-015-0159-4/}
}