TY  - JOUR
AU  - Cao, Xifang
AU  - Kong, Qingkai
AU  - Wu, Hongyou
AU  - Zettl, Anton
TI  - Sturm-Liouville Problems Whose Leading Coefficient Function Changes Sign
JO  - Canadian journal of mathematics
PY  - 2003
SP  - 724
EP  - 749
VL  - 55
IS  - 4
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CJM-2003-031-0/
DO  - 10.4153/CJM-2003-031-0
ID  - 10_4153_CJM_2003_031_0
ER  -