1. H. Poincaré. Les Methodes Nouvelles de la Mécanique Celeste, Vol. II, Dover, New York, 1957.
2. G. G. Stokes, On the Theory of Oscillatory Waves, Cambridge, Transactions, 8, 1847, pp. 441–473.
3. M. van Dyke, Perturbation Methods in Fluid Mechanics, Annotated Edition, Parabolic Press, Stanford, California, 1975.
4. P. F. Byrd and M. D. Friedman, Handbook of Elliptic Integrals for Engineers and Scientists, 2nd edition, Springer-Verlag, New York, 1971.
5. Ph.D. thesis at Caltech. A brief version appears in the work of J. D. Cole and J. Kevorkian, Nonlinear Differential Equations and Nonlinear Mechanics, (LaSalle and Lefschetz, editors), New York, Academic Press, 1963, pp. 113–120.