@article{ZVMMF_1993_33_4_a10,
     author = {S. A. Shishkin},
     title = {The problem of calculating a perturbed inverse matrix as a convergent product},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {624--631},
     publisher = {mathdoc},
     volume = {33},
     number = {4},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1993_33_4_a10/}
}