@article{DE_1989_25_3_a27,
     author = {T. L. Surin},
     title = {Exponents of regular {Lappo{\textendash}Danilevskiǐ} systems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {543--545},
     year = {1989},
     volume = {25},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_3_a27/}
}