@article{00733118, title = {Applications of the method of barriers. I: Some boundary-value problems.}, journal = {Georgian Mathematical Journal}, volume = {2}, year = {1995}, pages = {99-110}, doi = {10.1007/BF02257737}, zbl = {0833.34016}, language = {en}, url = {http://dml.mathdoc.fr/item/00733118} }
Rozov, N.Kh.; Sushko, V.G. Applications of the method of barriers. I: Some boundary-value problems.. Georgian Mathematical Journal, Tome 2 (1995) pp. 99-110. doi : 10.1007/BF02257737. http://gdmltest.u-ga.fr/item/00733118/