@article{IM2_1999_63_4_a9,
     author = {I. L. Kantor and A. I. Sirota and A. S. Solodovnikov},
     title = {Letter to the editor},
     journal = {Izvestiya. Mathematics},
     pages = {845},
     year = {1999},
     volume = {63},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1999_63_4_a9/}
}