1. Marchenko, V.A.: Sturm–Liouville Operators and Their Applications, Naukova Dumka, Kiev (1977) (Russian). Birkhauser, English transl (1986)
2. Levitan, B.M.: Inverse Sturm–Liouville Problems, Nauka, Moscow (1984) (Russian). English transl. VNU Sci. Press, Utrecht (1987)
3. Pöschel, J., Trubowitz, E.: Inverse Spectral Theory. Academic Press, New York (1987)
4. Freiling, G., Yurko, V.: Inverse Sturm–Liouville Problems and Their Applications. Nova Science Publishers, Huntington, NY (2001)
5. Agranovich, Z.S., Marchenko, V.A.: The Inverse Problem of Scattering Theory. Gordon and Breach, New York (1963)