Mustafin, M. A. On the Riesz basis of a sine system. (Russian) Zbl 0696.34013 Differ. Uravn. 25, No. 10, 1832-1833 (1989). Reviewer: N.Bozhinov MSC: 34B10 42C30 42C15 PDFBibTeX XMLCite \textit{M. A. Mustafin}, Differ. Uravn. 25, No. 10, 1832--1833 (1989; Zbl 0696.34013)
Semerdzhieva, R. I. On a difference method for solving a class of hyperbolic equations with degeneration of the order. (Russian) Zbl 0685.65084 Differ. Uravn. 25, No. 10, 1755-1766 (1989). Reviewer: S.Spassov MSC: 65M06 35L15 35L80 PDFBibTeX XMLCite \textit{R. I. Semerdzhieva}, Differ. Uravn. 25, No. 10, 1755--1766 (1989; Zbl 0685.65084)