@incollection{
    NR94:tfkrr,
    editor = "Lakemeyer, G. and Nebel, B.",
    author = {Niemel{\"a}, Ilkka and Rintanen, J.},
    chapter = "",
    publisher = "Springer-Verlag",
    title = "On the Impact of Stratification on the Complexity of Nonmonotonic Reasoning",
    booktitle = "Foundations of Knowledge Representation and Reasoning",
    address = "Berlin",
    month = "",
    year = "1994",
    pages = "275--295"
}