Theorems analogous to those of V. A. Marchenko [Dokl. Akad. Nauk SSSR, n. Ser. 72, 457-460 (1950; Zbl 0040.34301)] and H. Hochstadt [J. Differ. Equations 17, 220-235 (1975; Zbl 0266.34027)] are proved for the boundary value problem
where are positive with absolutely continuous derivatives, are real, and The case of two eigenparameter-dependent boundary conditions is also considered.