@article{DAN_1996_351_4_a3,
     author = {V. V. Dubrovskii},
     title = {Estimation of the difference of spectral functions with brackets},
     journal = {Doklady Akademii Nauk},
     pages = {452--453},
     year = {1996},
     volume = {351},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1996_351_4_a3/}
}