1. M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions,” Dover, New York (1965).
2. W.F. Ames, “Nonlinear Ordinary Differential Equations in Transport Processes,” Academic Press, New York (1968).
3. W.F. Ames, “Nonlinear Partial Differential Equations in Engineering. II,” Academic Press, New York (1972).
4. D.G. Aronson and H.F. Weinberger, in “Partial Differential Equations and Related Topics,” [Ed. J.A. Goldstein], Lect. Notes Math., 446, Springer-Verlag, Berlin (1975) pp5–49.
5. G. Baumann, “Lie Symmetries of Differential Equations”, Universität Ulm, preprint (1992).