@article{MZM_1990_48_5_a21,
     author = {M. M. Sirazhudinov},
     title = {Periodic solutions of a~first-order elliptic system},
     journal = {Matemati\v{c}eskie zametki},
     pages = {153--155},
     publisher = {mathdoc},
     volume = {48},
     number = {5},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_5_a21/}
}