@inbook{madrid_ojeda-aciego_2009, 
  title={On Coherence and Consistence in Fuzzy Answer Set Semantics for Residuated Logic Programs}, 
  DOI={10.1007/978-3-642-02282-1_8}, 
  publisher={Springer Berlin Heidelberg}, 
  author={Madrid and Ojeda-Aciego}, 
  year={2009}
  }