Rong, Yaoteng The mean value formulas of nonhomogeneous ultra-hyperbolic equations and their applications. (Chinese. English summary) Zbl 0925.35016 Pure Appl. Math. 2, 93-108 (1986). MSC: 35B05 Oscillation, zeros of solutions, mean value theorems, etc. in context of PDEs 35L05 Wave equation 35L99 Hyperbolic equations and hyperbolic systems Keywords:Huyghens principle PDF BibTeX XML Cite \textit{Y. Rong}, Pure Appl. Math. 2, 93--108 (1986; Zbl 0925.35016) OpenURL