@article{UZMU_1950_146_146_a4,
     author = {L. Tclaf},
     title = {On condition of {Jacobi} positivity of second variation},
     journal = {Uchenye Zapiski Moskovskogo Gosudarstvennogo Universiteta},
     pages = {116--125},
     publisher = {mathdoc},
     volume = {146},
     number = {146},
     year = {1950},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZMU_1950_146_146_a4/}
}