@article{JLT_2011_21_1_JLT_2011_21_1_a1,
     author = {T. B. Madsen and A. Swann },
     title = {Invariant {Strong} {KT} {Geometry} on {Four-Dimensional} {Solvable} {Lie} {Groups}},
     journal = {Journal of Lie theory},
     pages = {55--7},
     year = {2011},
     volume = {21},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/JLT_2011_21_1_JLT_2011_21_1_a1/}
}