@article{DE_1989_25_3_a17,
     author = {\`E. I. Grudo},
     title = {A formula for periodic solutions of a linear nonhomogeneous differential system with a {Jordan} cell},
     journal = {Differencialʹnye uravneni\^a},
     pages = {521--523},
     publisher = {mathdoc},
     volume = {25},
     number = {3},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_3_a17/}
}