@article{01370653, title = {Weakly hyperbolic equations with time degeneracy in Sobolev spaces.}, journal = {Abstract and Applied Analysis}, volume = {2}, year = {1997}, pages = {239-256}, doi = {10.1155/S1085337597000377}, zbl = {0938.35109}, language = {en}, url = {http://dml.mathdoc.fr/item/01370653} }
Reissig, Michael. Weakly hyperbolic equations with time degeneracy in Sobolev spaces.. Abstract and Applied Analysis, Tome 2 (1997) pp. 239-256. doi : 10.1155/S1085337597000377. http://gdmltest.u-ga.fr/item/01370653/