Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1969_5_11_a1, author = {V. A. Il'in}, title = {Fourier series in fundamental systems of functions of the {Beltrami} operator}, journal = {Differencialʹnye uravneni\^a}, pages = {1940--1978}, publisher = {mathdoc}, volume = {5}, number = {11}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1969_5_11_a1/} }
V. A. Il'in. Fourier series in fundamental systems of functions of the Beltrami operator. Differencialʹnye uravneniâ, Tome 5 (1969) no. 11, pp. 1940-1978. http://geodesic.mathdoc.fr/item/DE_1969_5_11_a1/