A Canonical Approach to Duality Transformations
  We show that Buscher's abelian duality transformation rules can be recovered in a very simple way by performing a canonical transformation first suggested by Giveon, Rabinovici and Veneziano. We explore the properties of this transformation, and also discuss some aspects of non-abelian duality. 
E. Alvarez, L. Alvarez-Gaume and Y. Lozano