@article{DAN_1978_240_3_a7,
     author = {M. A. Krasnosel'skii and N. A. Bobylev and \`E. M. Muhamadiev},
     title = {On a scheme for studying degenerate extremals of functionals in the classical calculus of variations},
     journal = {Doklady Akademii Nauk},
     pages = {530--533},
     publisher = {mathdoc},
     volume = {240},
     number = {3},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_240_3_a7/}
}