@ARTICLE\{IMM1987-0282,
    author       = "H. Juel and R. F. Love",
    title        = "Duality in constrained location problems",
    year         = "1987",
    pages        = "281-284",
    journal      = "Operations Research Letters",
    volume       = "6",
    editor       = "",
    number       = "",
    publisher    = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/282-full.html"
}