@ARTICLE\{IMM2001-01095,
    author       = "K. Bormann",
    title        = "Occlusion culliing in large virtual environments",
    year         = "2001",
    pages        = "477-495",
    journal      = "Presence",
    volume       = "10",
    editor       = "",
    number       = "5",
    publisher    = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1095-full.html"
}