@inproceedings(Nguyen09CSP, 
  author      = {Linh Anh Nguyen}, 
  title       = {Extending the Description Horn Logic {DHL}}, 
  booktitle   = {Proceedings of CS\&P'2009}, 
  editor      = {L. Czaja and M. Szczuka}, 
  pages       = {419-430},
  year        = {2009}
)