Birman, M. Sh. On the spectrum of Schrödinger’s and Dirac’s operators. (Russian) Zbl 0104.07702 Dokl. Akad. Nauk SSSR 129, 239-241 (1959). MSC: 35P05 47A10 35J10 35Q40 PDFBibTeX XMLCite \textit{M. Sh. Birman}, Dokl. Akad. Nauk SSSR 129, 239--241 (1959; Zbl 0104.07702)
Zhukov, A. I. A limit theorem for difference operators. (Russian) Zbl 0092.09802 Usp. Mat. Nauk 14, No. 3(87), 129-136 (1959). Reviewer: D. I. Mangeron MSC: 65Q10 39A70 65N22 60F99 PDFBibTeX XMLCite \textit{A. I. Zhukov}, Usp. Mat. Nauk 14, No. 3(87), 129--136 (1959; Zbl 0092.09802)
Huber, Heinz Zur analytischen Theorie hyperbolischer Raumformen und Bewegungsgruppen. (German) Zbl 0089.06101 Math. Ann. 138, 1-26 (1959). Reviewer: F. van der Blij (Utrecht) MSC: 30F35 PDFBibTeX XMLCite \textit{H. Huber}, Math. Ann. 138, 1--26 (1959; Zbl 0089.06101) Full Text: DOI EuDML