@article{VMUMM_2012_4_a15,
     author = {L. S. Otradnova},
     title = {Maximum of action for {Hamiltonian} systems with unilateral constraints},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {70--72},
     publisher = {mathdoc},
     number = {4},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2012_4_a15/}
}