@InProceedings{	  BeckertHaehnleEAld98,
  author	= {Bernhard Beckert and Reiner H\"ahnle and Felip Many\`a},
  title		= {Transformations between Signed and Classical Clause Logic},
  booktitle	= {First International Workshop on Labelled Deduction},
  venue         = {Freiburg, Germany},
  publisher	= {Department of Computer Science, University of Freiburg},
  year		= {1998}
}