Feller, M. N. Boundary-value problems for a nonlinear hyperbolic equation with variable coefficients and the Lévy Laplacian. II. (English. Russian original) Zbl 1334.35411 Math. Notes 97, No. 6, 930-936 (2015); translation from Mat. Zametki 97, No. 6, 917-924 (2015). MSC: 35R15 PDFBibTeX XMLCite \textit{M. N. Feller}, Math. Notes 97, No. 6, 930--936 (2015; Zbl 1334.35411); translation from Mat. Zametki 97, No. 6, 917--924 (2015) Full Text: DOI
Feller, M. N. Boundary-value problems for a nonlinear hyperbolic equation with variable coefficients and the Lévy Laplacian. (English. Russian original) Zbl 1323.35206 Math. Notes 96, No. 3, 423-431 (2014); translation from Mat. Zametki 96, No. 3, 440-449 (2014). MSC: 35R15 PDFBibTeX XMLCite \textit{M. N. Feller}, Math. Notes 96, No. 3, 423--431 (2014; Zbl 1323.35206); translation from Mat. Zametki 96, No. 3, 440--449 (2014) Full Text: DOI
Il’inskij, A. I. The arithmetic of the characteristic Polya functions. (English) Zbl 0401.60006 Math. Notes 21, 400-405 (1977). MSC: 60B15 PDFBibTeX XMLCite \textit{A. I. Il'inskij}, Math. Notes 21, 400--405 (1977; Zbl 0401.60006) Full Text: DOI