@article{IVM_1991_5_a14,
     author = {S. G. Kal'nei},
     title = {Necessary and sufficient conditions for the summability of {Jacobi} series},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {75--78},
     year = {1991},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1991_5_a14/}
}