@article{05169466, title = {Carleman estimates for second-order hyperbolic equations.}, journal = {Sibirskij Matematicheskij Zhurnal}, volume = {47}, year = {2006}, pages = {169-187}, zbl = {1113.35112}, language = {en}, url = {http://dml.mathdoc.fr/item/05169466} }
Romanov, V.G. Carleman estimates for second-order hyperbolic equations.. Sibirskij Matematicheskij Zhurnal, Tome 47 (2006) pp. 169-187. http://gdmltest.u-ga.fr/item/05169466/