@article{05875551,
title = {On smoothness of a fundamental solution to a second order hyperbolic equation.},
journal = {Sibirskij Matematicheskij Zhurnal},
volume = {50},
year = {2009},
pages = {883-889},
zbl = {1224.35256},
language = {en},
url = {http://dml.mathdoc.fr/item/05875551}
}
Romanov, V.G. On smoothness of a fundamental solution to a second order hyperbolic equation.. Sibirskij Matematicheskij Zhurnal, Tome 50 (2009) pp. 883-889. http://gdmltest.u-ga.fr/item/05875551/