@article{VUU_2008_2_a13,
     author = {Yu. F. Dolgii},
     title = {Construction of the approached characteristic equations for periodic systems with aftereffect and determinants of perturbation},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {42--43},
     publisher = {mathdoc},
     number = {2},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2008_2_a13/}
}