[1] C. D. Ahlbrandt D. B. Hinton. R. T. Lewis:
Necessary and sufficient conditions for the discreteness of the spectrum of certain singular differential operators. Canad. J. Math. 33 (1981), 229-246.
DOI 10.4153/CJM-1981-019-1 |
MR 0608867
[2] C. D. Ahlbrandt D. B. Hinton. R. T. Lewis:
The effect of variable change on oscillation and disconjugacy criteria with applications to spectral theory and asymptotic theory. J. Math. Anal. Appl. 81 (1981), 234-277.
DOI 10.1016/0022-247X(81)90060-3 |
MR 0618771
[3] W. A. Coppel:
Disconjugacy. Lectures Notes in Math., No. 220, Springer-Verlag, Berlin, 1971.
MR 0460785 |
Zbl 0224.34003
[4] O. Došlý:
Spectral properties of a class of singular differential operators. To appear in Math. Nachr.
MR 1484668
[5] O. Došlý J. Komenda:
Conjugacy criteria and principal solutions of self-adjoint differential equations. Arch. Math. (Brno) 31 (1995), 217-238.
MR 1368260
[8] I. M. Glazman: Direct Methods of Qualitative Analysis of Singular Differential Operators. Jerusalem, 1965.
[10] D. B. Hinton R. T. Lewis:
Discrete spectra criteria for singular differential operators with middle terms. Math. Proc. Cambridge Philos. Soc. 77 (1975), 337-347.
MR 0367358
[12] M. A. Naimark:
Linear Differential Operators. Part II. Ungar, New York, 1968.
Zbl 0227.34020
[13] W. T. Reid:
Sturmian Theory for Ordinary Differential Equations. Springer-Verlag, New York, 1980.
MR 0606199 |
Zbl 0459.34001
[14] R. L. Sternberg:
Variational methods and nonoscillatory theorems for systems of differential equations. Duke J. Math. 19 (1952), 311-322.
MR 0048668
[15] C. A. Swanson:
Comparison and Oscillation Theory of Linear Differential Equations. Acad. Press, New York, 1968.
MR 0463570 |
Zbl 0191.09904