Spectral Geometry of Compact Hermitian Symmetric Submanifolds. Seiichi Udagawa — 1986 Mathematische Zeitschrift
Compact Kaehler manifolds and the eigenvalues of the Laplacian Seiichi Udagawa — 1988 Colloquium Mathematicae
Stability, complex-analyticity and constancy of pluriharmonic maps from compact Kaehler manifolds. Yoshihiro Ohnita; Seiichi Udagawa — 1990 Mathematische Zeitschrift