1. Some recent review articles are by Pohlmeyer, K., Nato Advanced Study Institutes Series, Vol. 30, edited by L. Streit (1978) 63; Rajaraman, R., Lectures delivered at Panchgani Winter School in High Energy Physics, India (1978);
2. Jackiw, R., Phys. Reports 23C, 273 (1976).
3. Coleman, S., and Weinberg, E., Phys. Rev. D7, 1888 (1973).
4. Murphy, G.M., Ordinary Differential Equations and Their Solutions, Chapter 3, Van Nostrand, New York, 1960.
5. Lee, T.D., in Proc. of the Symposium on Frontier Problems in High Energy Physics, Pisa, 1976 (unpublished).