TY  - JOUR
AU  - Hughes, Edward
TI  - Perturbation Theorems for Relative Spectral Problems
JO  - Canadian journal of mathematics
PY  - 1972
SP  - 72
EP  - 81
VL  - 24
IS  - 1
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1972-009-8/
DO  - 10.4153/CJM-1972-009-8
ID  - 10_4153_CJM_1972_009_8
ER  -