@article{
    ekmdam,
    author = {Eiter, T. and Kilpel{\"a}inen, P. and Mannila, Heikki},
    volume = "59",
    journal = "Discrete Applied Mathematics",
    year = "1995",
    pages = "23-31",
    title = "Recognizing renamable generalized propositional Horn formulas is NP-complete"
}