@article{00645197, title = {On the correct formulation of a multidimensional problem for strictly hyperbolic equations of higher order.}, journal = {Georgian Mathematical Journal}, volume = {1}, year = {1994}, pages = {141-150}, doi = {10.1007/BF02254728}, zbl = {0819.35091}, language = {en}, url = {http://dml.mathdoc.fr/item/00645197} }
Kharibegashvili, S. On the correct formulation of a multidimensional problem for strictly hyperbolic equations of higher order.. Georgian Mathematical Journal, Tome 1 (1994) pp. 141-150. doi : 10.1007/BF02254728. http://gdmltest.u-ga.fr/item/00645197/