Kadelburg, Eh.; Martinović, M. The spectral function of a second order functional-differential operator. (Russian) Zbl 0693.34070 Differ. Uravn. 25, No. 11, 1882-1888 (1989). Reviewer: M.Tvrdy MSC: 34K10 34L99 PDFBibTeX XMLCite \textit{Eh. Kadelburg} and \textit{M. Martinović}, Differ. Uravn. 25, No. 11, 1882--1888 (1989; Zbl 0693.34070)
Volkov, V. E. On the boundedness of the number of orthogonal solutions of the equation \(-u''+q(x)u=\lambda u\). (Russian) Zbl 0693.34037 Differ. Uravn. 25, No. 11, 1862-1866 (1989). Reviewer: D.Bobrowski MSC: 34C11 PDFBibTeX XMLCite \textit{V. E. Volkov}, Differ. Uravn. 25, No. 11, 1862--1866 (1989; Zbl 0693.34037)
Tsapenko, N. E. New formulae for approximate solution of one-dimensional wave equation. (Russian) Zbl 0693.34008 Differ. Uravn. 25, No. 11, 1941-1946 (1989). Reviewer: L.Janos MSC: 34A45 34C20 PDFBibTeX XMLCite \textit{N. E. Tsapenko}, Differ. Uravn. 25, No. 11, 1941--1946 (1989; Zbl 0693.34008)