Duality methods for a class of quasilinear systems
  Duality methods are used to generate explicit solutions to nonlinear Hodge systems, demonstrate the well-posedness of boundary value problems, and reveal, via the Hodge-B\"acklund transformation, underlying symmetries among superficially different forms of the equations. 
Antonella Marini and Thomas H. Otway
math.AP math-ph math.MP