@article{IVM_1991_11_a5,
     author = {O. A. Ziza},
     title = {Absolute summability of orthogonal series by $(\varphi,\lambda)$ methods},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {25--36},
     year = {1991},
     number = {11},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1991_11_a5/}
}