Weber, Albin Über das wesentliche Spektrum des gestoerten polyharmonischen Operators. II. (German) Zbl 0495.35061 Math. Nachr. 95, 195-208 (1980). MSC: 35P05 35J55 31B30 PDFBibTeX XMLCite \textit{A. Weber}, Math. Nachr. 95, 195--208 (1980; Zbl 0495.35061) Full Text: DOI
Samojlenko, V. G. A difference operator with infinitely many variables. (English. Russian original) Zbl 0455.47023 Ukr. Math. J. 31, 465-467 (1980); translation from Ukr. Mat. Zh. 31, 586-588 (1979). MSC: 47B39 47A55 47A20 47B25 PDFBibTeX XMLCite \textit{V. G. Samojlenko}, Ukr. Math. J. 31, 465--467 (1980; Zbl 0455.47023); translation from Ukr. Mat. Zh. 31, 586--588 (1979) Full Text: DOI
Herrero, Domingo A. Lifting essentially \((G_1)\) operators. (English) Zbl 0441.47004 Rev. Unión Mat. Argent. 29, 113-119 (1980). MSC: 47A10 47A55 47L30 PDFBibTeX XMLCite \textit{D. A. Herrero}, Rev. Unión Mat. Argent. 29, 113--119 (1980; Zbl 0441.47004)
Weber, Albin Über das wesentliche Spektrum des gestörten polyharmonischen Operators. (German) Zbl 0439.35051 Math. Nachr. 94, 57-67 (1980). MSC: 35P05 31C99 31B35 PDFBibTeX XMLCite \textit{A. Weber}, Math. Nachr. 94, 57--67 (1980; Zbl 0439.35051) Full Text: DOI