@article{DAN_1957_117_2_a1,
     author = {Yu. P. Ginzburg},
     title = {$J${-Non-stretching} operator functions},
     journal = {Doklady Akademii Nauk},
     pages = {171--173},
     publisher = {mathdoc},
     volume = {117},
     number = {2},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_117_2_a1/}
}