TY  - JOUR
AU  - Díaz, J. B.
TI  - Reflection principles for the iterated Helmholtz equation.
JO  - Collectanea mathematica
PY  - 1975
SP  - 253
EP  - 266
VL  - 26
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/CLTM_1975_1975_1_a19/
LA  - en
ID  - CLTM_1975_1975_1_a19
ER  -