Parametric Backlund transformations I: Phenomenology
  We begin an exploration of parametric Backlund transformations for hyperbolic Monge-Ampere systems. We compute invariants for such transformations and explore the behavior of four examples regarding their invariants, symmetries, and conservation laws. We prove some preliminary results and indicate directions for further research. 
Jeanne N. Clelland and Thomas A. Ivey