Higher order singular perturbation method for linear differential equations in Banach spaces Janusz Mika — 1976 Annales Polonici Mathematici
Existence and uniqueness of the solution to the critical problem in neutron transport theory Janusz Mika — 1971 Studia Mathematica
Asymptotic methods for singularly perturbed linear differential equations in Banach spaces Mika, Janusz — 1979 Equadiff IV
Singularly perturbed telegraph equations with applications in the random walk theory. Banasiak, Jacek; Mika, Janusz R. — 1998 Journal of Applied Mathematics and Stochastic Analysis