1. Ackerberg, R.C., O’Malley, R.E.: Boundary layer problems exhibiting resonance. Stud. Appl. Math. 49, 277–295 (1970)
2. Balser, W.: Formal Power Series and Linear Systems of Meromorphic Ordinary Differential Equations. Springer, New York (2000)
3. Benoît, É., Callot, J.-L., Diener, F., Diener, M.: Chasse au canard. Collect. Math. 31, 37–119 (1981)
4. Benoît, É., El Hamidi, A., Fruchard, A.: On combined asymptotic expansions in singular perturbations. Electron. J. Diff. Equat. 51, 1–27 (2002)
5. Benoît, É., Fruchard, A., Schäfke, R., Wallet, G.: Solutions surstables des équations différentielles complexes lentes-rapides à point tournant. Ann. Fac. Sci. Toulouse Math. VII 4, 627–658 (1998)