@article{01069382, title = {Complex powers of the wave operator.}, journal = {Portugaliae Mathematica. Nova S\'erie}, volume = {54}, year = {1997}, pages = {345-362}, zbl = {0891.35166}, language = {en}, url = {http://dml.mathdoc.fr/item/01069382} }
Joshi, M.S. Complex powers of the wave operator.. Portugaliae Mathematica. Nova Série, Tome 54 (1997) pp. 345-362. http://gdmltest.u-ga.fr/item/01069382/