Voir la notice de l'article provenant de la source Math-Net.Ru
@article{IVM_1975_8_a9, author = {I. N. Pak}, title = {The differentiability of sums of series of {Jacobi} polynomials}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {70--80}, publisher = {mathdoc}, number = {8}, year = {1975}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1975_8_a9/} }
I. N. Pak. The differentiability of sums of series of Jacobi polynomials. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 8 (1975), pp. 70-80. http://geodesic.mathdoc.fr/item/IVM_1975_8_a9/