@article{ISU_2014_14_2_a8,
     author = {V. A. Kovalev and Yu. N. Radayev},
     title = {On a~form of the first variation of the action integral over a~varied domain},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {199--209},
     publisher = {mathdoc},
     volume = {14},
     number = {2},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2014_14_2_a8/}
}