@article{DE_2004_40_2_a0,
     author = {N. V. Azbelev and E. I. Bravyi and S. A. Gusarenko},
     title = {On {Effective} {Solvability} {Conditions} for {Variational} {Problems}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {147--153},
     publisher = {mathdoc},
     volume = {40},
     number = {2},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2004_40_2_a0/}
}