@article{02214046, title = {Time deformations of powers of the wave operator.}, journal = {Zapiski Nauchnykh Seminarov POMI}, volume = {321}, year = {2005}, pages = {213-228}, zbl = {1100.35002}, language = {en}, url = {http://dml.mathdoc.fr/item/02214046} }
Khèkalo, S.P. Time deformations of powers of the wave operator.. Zapiski Nauchnykh Seminarov POMI, Tome 321 (2005) pp. 213-228. http://gdmltest.u-ga.fr/item/02214046/