@article{DAN_1995_343_4_a6,
     author = {P. L. Ul'yanov},
     title = {On equivalent conditions for the convergence of series and},
     journal = {Doklady Akademii Nauk},
     pages = {458--462},
     publisher = {mathdoc},
     volume = {343},
     number = {4},
     year = {1995},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1995_343_4_a6/}
}