@CONFERENCE\{IMM1999-0211,
    author       = "J. Larsen",
    title        = "Speeding up column generation in {VRPTW}",
    year         = "1999",
    pages        = "32-33",
    booktitle    = "Third Scandinavian Workshop in Linear Programming",
    volume       = "",
    series       = "",
    editor       = "Hans Bruun Nielsen",
    publisher    = "Informatics and Mathematical Modelling, Technical University of Denmark, {DTU}",
    organization = "",
    address      = "Richard Petersens Plads, Building 321, {DK-}2800 Kgs. Lyngby",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/211-full.html",
    isbn_issn    = "12"
}