Singular perturbation problems in chemical physics: analytic and computational methods

The matching method for asymptotic solugions in chemical lphysics problems / A.M. Il'in, L.A. Kalyakin, S.I. Maslennikov

Singularly perturbed problems with boundary and interior layers: theory and application / V.F. Butuzov, A.B. Vasilieva

Numerical methods for singularly perturbed boundary value problems modeling diffusion processes / V.L. Kolmogorov, G.I. Shishkin.