Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1971_7_9_a22, author = {V. S. Mokeichev}, title = {Periodic boundary value problems and {Riesz} bases}, journal = {Differencialʹnye uravneni\^a}, pages = {1714--1720}, publisher = {mathdoc}, volume = {7}, number = {9}, year = {1971}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1971_7_9_a22/} }
V. S. Mokeichev. Periodic boundary value problems and Riesz bases. Differencialʹnye uravneniâ, Tome 7 (1971) no. 9, pp. 1714-1720. http://geodesic.mathdoc.fr/item/DE_1971_7_9_a22/