Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1980_251_5_a10, author = {S. M. Ponomarev}, title = {On an eigenvalue problem for an equation of mixed type}, journal = {Doklady Akademii Nauk}, pages = {1070--1072}, publisher = {mathdoc}, volume = {251}, number = {5}, year = {1980}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1980_251_5_a10/} }
S. M. Ponomarev. On an eigenvalue problem for an equation of mixed type. Doklady Akademii Nauk, Tome 251 (1980) no. 5, pp. 1070-1072. http://geodesic.mathdoc.fr/item/DAN_1980_251_5_a10/