@article{DE_1988_24_9_a4,
     author = {S. A. Laptev},
     title = {A variational problem for a dynamic potential},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1509--1520},
     publisher = {mathdoc},
     volume = {24},
     number = {9},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1988_24_9_a4/}
}