@article{RG-Nguyen, 
  author       = {Linh Anh Nguyen},
  title        = {{Horn} Knowledge Bases in Regular Description Logics 
                  with {PTime} Data Complexity},
  journal      = {Fundamenta Informaticae},
  volume       = {104},
  number       = {4},
  pages        = {349-384},
  year         = {2010}
}