@article{JLT_2014_24_3_JLT_2014_24_3_a13,
     author = {V. Del Barco },
     title = {Symplectic {Structures} on {Nilmanifolds:} an {Obstruction} for their {Existence}},
     journal = {Journal of Lie theory},
     pages = {889--908},
     publisher = {mathdoc},
     volume = {24},
     number = {3},
     year = {2014},
     url = {http://geodesic.mathdoc.fr/item/JLT_2014_24_3_JLT_2014_24_3_a13/}
}