Pointwise Error Estimates for a Streamline Diffusion Finite Element Scheme. Koichi Niijima Numerische Mathematik
A Uniformly Convergent Difference Scheme for a Semilinear Singular Perturbation Problem. Koichi Niijima — 1984 Numerische Mathematik
On a Difference Scheme of Exponential Type for a Nonlinear Singular Perturbation Problem. Koichi Niijima — 1985 Numerische Mathematik