@article{SM_1995_82_1_a2,
     author = {S. V. Burtsev},
     title = {Theorems on the~existence of an~implicit function in the~theory of necessary and sufficient conditions for an~extremum},
     journal = {Sbornik. Mathematics},
     pages = {65--85},
     publisher = {mathdoc},
     volume = {82},
     number = {1},
     year = {1995},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1995_82_1_a2/}
}