時田 武

On the behavior of the solutions of (λ-Δ)u=f as λ→∞ 

Memoirs of the Faculty Education Fukui University Series II (Natural Science) (46) 1995年  

Initial boundary value problems of fourth order hyperbolic equations 

Journal of Mathematics of Kyoto University 19(3) 1979年  

Exponential decay of solutions for the wave pquation in the exterior domain with spherical boundary 

Journal of Mathematics of Kyoto University 12(2) 1972年