@article{TMF_2015_184_1_a3,
     author = {V. G. Marikhin},
     title = {Action as an~invariant of {B\"acklund} transformations for {Lagrangian} systems},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {71--78},
     year = {2015},
     volume = {184},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2015_184_1_a3/}
}