@article{TMF_2018_196_2_a0,
     author = {H. Baran and I. S. Krasil'shchik and O. I. Morozov and P. Voj\v{c}\'ak},
     title = {Nonlocal symmetries of integrable linearly degenerate equations: {A~comparative} study},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {169--192},
     year = {2018},
     volume = {196},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2018_196_2_a0/}
}