@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/} }