@CONFERENCE\{IMM1987-01898,
    author       = "M. R. Hansen",
    title        = "Algebraic Optimization of Recursive Database Queries",
    year         = "1987",
    pages        = "223-230",
    booktitle    = "Intelligence Integration",
    volume       = "",
    series       = "",
    editor       = "",
    publisher    = "Canadian Information Processing Society",
    organization = "",
    address      = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1898-full.html"
}