@article{ISU_2021_21_4_a0,
     author = {I. G. Guseinov and R. M. Gadzhimirzaev},
     title = {Two-dimensional limit series in ultraspherical {Jacobi} polynomials and their approximative properties},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {422--433},
     publisher = {mathdoc},
     volume = {21},
     number = {4},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2021_21_4_a0/}
}