@article{RLIN_1999_9_10_2_a0,
     author = {Citti, Giovanna and Lanconelli, Ermanno and Montanari, Annamaria},
     title = {On the smoothness of viscosity solutions of the prescribed {Levi-curvature} equation},
     journal = {Atti della Accademia nazionale dei Lincei. Rendiconti Lincei. Matematica e applicazioni},
     pages = {61--68},
     publisher = {mathdoc},
     volume = {Ser. 9, 10},
     number = {2},
     year = {1999},
     zbl = {1010.35024},
     mrnumber = {708370},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RLIN_1999_9_10_2_a0/}
}