@CONFERENCE\{IMM2003-01749,
    author       = "N. R. Kristensen and H. Madsen and S. B. J{\o}rgensen",
    title        = "A Unified Framework for Systematic Model Improvement",
    year         = "2003",
    month        = "jun",
    booktitle    = "{PSE} 2003, Kun Ming, Kina, Juni 2003",
    volume       = "",
    series       = "",
    editor       = "",
    publisher    = "",
    organization = "",
    address      = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1749-full.html"
}