@TECHREPORT\{IMM1997-03842,
    author       = "V. V. Vidal and P. M. Borges",
    title        = "A global maximum principle applied to a model of consumer brand choice",
    year         = "1997",
    pages        = "20",
    number       = "",
    series       = "",
    institution  = "{IMM,} {DTU}",
    address      = "",
    type         = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/3842-full.html"
}