@article{02163655, title = {New singular solutions of Protter's problem for the 3D wave equation.}, journal = {Abstract and Applied Analysis}, volume = {2004}, year = {2004}, pages = {315-335}, doi = {10.1155/S1085337504306111}, zbl = {1086.35064}, language = {en}, url = {http://dml.mathdoc.fr/item/02163655} }
Grammatikopoulos, M.K.; Popivanov, N.I.; Popov, T.P. New singular solutions of Protter's problem for the 3D wave equation.. Abstract and Applied Analysis, Tome 2004 (2004) pp. 315-335. doi : 10.1155/S1085337504306111. http://gdmltest.u-ga.fr/item/02163655/