1. Topics in singular perturbations;O'Malley;Advan. Math.,1968
2. On the differential equations of the simplest boundary-layer problems;Weyl;Ann. Math.,1942
3. D. S. Cohen and P. A. Lagerstrom, Asymptotic theory of a model equation, to be published.
4. On a nonlinear boundary value problem involving a small parameter;Erdélyi;J. Australian Math. Soc.,1962
5. On boundary problems for the equation ϵy″ + f(x, y, y′, ϵ) for small ϵ;Bris;Dokl. Akad. Nauk SSSR (N. S.),1954