@article{JLT_2017_27_4_JLT_2017_27_4_a2,
     author = {A. Haji-Badali and R. Karami},
     title = {Ricci {Solitons} on {Four-dimensional} {Neutral} {Lie} {Groups}},
     journal = {Journal of Lie theory},
     pages = {943--967},
     year = {2017},
     volume = {27},
     number = {4},
     url = {http://geodesic.mathdoc.fr/item/JLT_2017_27_4_JLT_2017_27_4_a2/}
}