@article{DAN_1988_300_6_a9,
     author = {M. S. Syavavko},
     title = {Rational approximations of the fundamental matrix of systems of},
     journal = {Doklady Akademii Nauk},
     pages = {1325--1328},
     publisher = {mathdoc},
     volume = {300},
     number = {6},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_300_6_a9/}
}