1. Gardner, C., Green, I., Kruskal, M., and Miura, R., A method for solving the
Korteweg–de Vries equation, Phys. Rev. Lett., 1967,
vol. 19, pp. 1095–1098.
2. Faddeev, L.D., Properties of the $$S
$$-matrix of the one-dimensional
Schrödinger equation, Am. Math. Soc. Transl. Ser.
2 , 1967, vol. 65, pp. 139–166.
3. Marchenko, V.A., Operatory Shturma–Liuvillya i ikh
prilozheniya (Sturm–Liouville Operators and Applications), Kiev: Nauk.
Dumka, 1977.
4. Levitan, B.M., Obratnye zadachi
Shturma–Liuvillya (Inverse Sturm–Liouville problems), Moscow: Nauka,
1984.
5. Lax, P.D., Integrals of nonlinear equations of evolution and solitary waves,
Commun. Pure Appl. Math., 1968, vol. 21,
pp. 467–490.