@article{
    eitergottlobtods,
    author = "Eiter, T. and Gottlob, G. and Mannila, Heikki",
    title = "Disjunctive Datalog",
    journal = "ACM Transactions on Database Systems",
    number = "3",
    month = "September",
    volume = "22",
    year = "1997",
    pages = "364-418"
}