1. 1. A A Nabiev and I M Guseinov, On the Jost solutions of the Schrödinger-type equations with a polynomial energy-dependent potential, Inverse Problems, 22 (2006) 55-67.
2. 2. A. M. Savchuk and A. A. Shkalikov, Sturm-Liouville operators with singular potentials, Mat. Zametki (Math. Notes) 66(6) (1999), 897-912 (in Russian). TRANSFORMATION OPERATORS 149.
3. 3. A. M. Savchuk, On eigenvalues and eigenfunctions of Sturm-Liouville operators with singular potentials, Mat. Zametki (Math. Notes) 69(2) (2001), 277-285 (in Russian).
4. 4. A. M. Savchuk and A. A. Shkalikov, Sturm-Liouville operators with distributional potentials, Trudy Moskov. Mat. Obshch. (Trans. Moscow Math. Soc.), 64 (2003), to appear (in Russian).
5. 5. A. Ya. Povzner, On differential Sturm-Liouville operators on semiaxis, Math. USSR-Sb. 23(65) (1948), 3-52.