Pa. Binding et Pj. Browne, OSCILLATION-THEORY FOR INDEFINITE STURM-LIOUVILLE PROBLEMS WITH EIGENPARAMETER-DEPENDENT BOUNDARY-CONDITIONS, Proceedings of the Royal Society of Edinburgh. Section A. Mathematics, 127, 1997, pp. 1123-1136
In previous papers we have studied oscillation properties of Sturm-Lio
uville problems (-py')' + qy = lambda ry, with lambda-dependent bounda
ry conditions, under various 'definiteness' conditions. Here we presen
t a new, unified, approach which also covers cases previously untreate
d, e.g. of semidefinite weight, and also the fully indefinite problem.