Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1991_27_11_a18, author = {I. P. Polovinkin}, title = {The converse of the mean-value theorem for the wave equation}, journal = {Differencialʹnye uravneni\^a}, pages = {1987--1990}, publisher = {mathdoc}, volume = {27}, number = {11}, year = {1991}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1991_27_11_a18/} }
I. P. Polovinkin. The converse of the mean-value theorem for the wave equation. Differencialʹnye uravneniâ, Tome 27 (1991) no. 11, pp. 1987-1990. http://geodesic.mathdoc.fr/item/DE_1991_27_11_a18/