@article{RM_1999_54_1_a12,
     author = {S. P. Novikov and A. S. Schwarz},
     title = {Discrete {Lagrangian} systems on graphs. {Symplectic-topological} properties},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {258--259},
     publisher = {mathdoc},
     volume = {54},
     number = {1},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1999_54_1_a12/}
}