@article{SM_1981_39_4_a7,
     author = {S. A. Apresyan},
     title = {Letter to the {Editor}},
     journal = {Sbornik. Mathematics},
     pages = {559},
     publisher = {mathdoc},
     volume = {39},
     number = {4},
     year = {1981},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1981_39_4_a7/}
}