@Unpublished{DJDHughes:hybrid,
  author    =  {Hughes, Dominic J.D.},
  title     =  {A classical sequent calculus free of structural rules},
  journal   =  {Annals of Pure and Applied Logic},
  volume    =  {161},
  issue     =  {10},
  pages     =  {1244--1253},
  year      =  {2010},
  month     =  {July},
  note      =  {Archived as math.LO/0506463 at arXiv.org}
}