@ARTICLE\{IMM1986-03690,
    author       = "V. V. Vidal",
    title        = "A Global Maximum Principle for Discrete-Time Control Problems",
    year         = "1986",
    keywords     = "Maximum principle, control, optimization",
    pages        = "150-162",
    journal      = "Engineering Optimization",
    volume       = "10",
    editor       = "",
    number       = "2",
    publisher    = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/3690-full.html"
}