@article{MZM_1987_42_1_a12,
     author = {N. N. Amosova},
     title = {A supplement to {W.~Richter's} theorem},
     journal = {Matemati\v{c}eskie zametki},
     pages = {120--123},
     publisher = {mathdoc},
     volume = {42},
     number = {1},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1987_42_1_a12/}
}