@article{SIGMA_2014_10_a50,
     author = {Freddy Cachazo and Lionel Mason and David Skinner},
     title = {Gravity in {Twistor} {Space} and~its {Grassmannian} {Formulation}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2014},
     volume = {10},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2014_10_a50/}
}