@article{INTO_2018_148_a6,
     author = {E. A. Kudryavtseva and D. A. Fedoseev},
     title = {Superintegrable {Bertrand} {Natural} {Mechanical} {Systems}},
     journal = {Itogi nauki i tehniki. Sovremenna\^a matematika i e\"e prilo\v{z}eni\^a. Temati\v{c}eskie obzory},
     pages = {37--57},
     publisher = {mathdoc},
     volume = {148},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTO_2018_148_a6/}
}