Fuchssteiner, Benno: Applications of analytic and geometric methods to nonlinear differential equations : [proceedings of the NATO Advanced Research Workshop on Applications of Analytic and Geometric Methods to Nonlinear Differential Equations, Exeter, U.K., July 14 - 19, 1992] (NATO ASI series : Series C, Computer and physical sciences / Coupling of completely integrable systems : the perturbation bundle. . In: Applications of analytic and geometric methods to nonlinear differential equations : [proceedings of the NATO Advanced Research Workshop on Applications of Analytic and Geometric Methods to Nonlinear Differential Equations, Exeter, U.K., July 14 - 19, 1992] (NATO ASI series : Series C, Computer and physical sciences. Vol.1993, page125138