@TECHREPORT\{IMM1986-03817,
    author       = "V. V. Vidal",
    title        = "Sufficient conditions for the convexity of the perturbation function",
    year         = "1986",
    pages        = "4",
    number       = "",
    series       = "",
    institution  = "{IMSOR,} {DTH}",
    address      = "",
    type         = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/3817-full.html"
}