@CONFERENCE\{IMM1992-01029,
    author       = "B. K. Ersb{\o}ll and K. Conradsen",
    title        = "A strategy for grading natural materials using a two-step classification procedure",
    year         = "1992",
    month        = "oct",
    pages        = "12",
    booktitle    = "{SPIE,} Boston",
    volume       = "",
    series       = "{SPIE} proceedings series",
    editor       = "",
    publisher    = "",
    organization = "",
    address      = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1029-full.html"
}