Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DAN_1989_309_6_a5, author = {Yu. V. Pokorny and O. M. Penkin}, title = {Sturm theorems for equations on graphs}, journal = {Doklady Akademii Nauk}, pages = {1306--1308}, publisher = {mathdoc}, volume = {309}, number = {6}, year = {1989}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1989_309_6_a5/} }
Yu. V. Pokorny; O. M. Penkin. Sturm theorems for equations on graphs. Doklady Akademii Nauk, Tome 309 (1989) no. 6, pp. 1306-1308. http://geodesic.mathdoc.fr/item/DAN_1989_309_6_a5/