@TechReport{tr223,
  author = 	 {Jochen Eisinger and Felix Klaedtke},
  title = 	 {Don't Care Words with an Application to the Automata-based Approach for Real Addition},
  institution =  {Institut f{\"u}r Informatik, Universit{\"a}t Freiburg},
  year = 	 {2006},
  number = 	 {223},
}