@InProceedings{BeckertHaehnleManya99,
  author    = {Bernhard Beckert and Reiner H{\"a}hnle and Felip Many{\`a}},
  title     = {Transformations between Signed and Classical Clause Logic},
  booktitle = {International Symposium on Multiple-Valued Logic ({ISMVL} 1999)},
  venue     = {Freiburg, Germany},
  publisher = {{IEEE} Computer Society},
  year      = {1999}
}