1. Boundary layer problems in applied mechanics;Carrier,1953
2. Introduction to Non-linear Mechanics;Kryloff,1947
3. Problems in singular perturbation theory;Cochran,1962
4. An expansion method for treating singular perturbation problems;Nayfeh;J. math. Phys.,1965
5. Numerical study of the periodic solutions of the Van der Pol equation;Urabe,1963