@ARTICLE\{IMM2002-01563,
    author       = "F. Nielson and H. Riis Nielson and R. R. Hansen",
    title        = "Validating Firewalls using Flow Logics",
    year         = "2002",
    pages        = "381-418",
    journal      = "Theoretical Computer Science",
    volume       = "283",
    editor       = "",
    number       = "2",
    publisher    = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1563-full.html"
}