@article{TMF_1986_69_3_a12,
     author = {I. V. Poplavskii},
     title = {Generalized {Darboux--Crum--Krein} transformations},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {475--479},
     publisher = {mathdoc},
     volume = {69},
     number = {3},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1986_69_3_a12/}
}