@article{DE_1993_29_8_a16,
     author = {V. M. Savchin},
     title = {A criterion for the existence of generalized integral variational principles for given equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1425--1432},
     publisher = {mathdoc},
     volume = {29},
     number = {8},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1993_29_8_a16/}
}