@unpublished{
    Niemela2000:cl,
    author = {Niemel{\"a}, Ilkka},
    note = "Lecture notes for a tutorial given at the First International Conference on Computational Logic, Imperial College, London, UK, July 24--28, 2000. 72 pages.",
    url = "http://www.tcs.hut.fi/~ini/",
    year = "2000",
    month = "",
    title = "Stable Model Semantics: From Theory to Implementations and Applications"
}