@ARTICLE\{IMM2002-01637,
    author       = "B. Norden and Y. Zolotaryuk and P. L. Christiansen and A. V. Zolotaryuk",
    title        = "Ratchet device with broken friction symmetry",
    year         = "2002",
    pages        = "2601-2603",
    journal      = "Applied Physics Letters",
    volume       = "80",
    editor       = "",
    number       = "14",
    publisher    = "",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/1637-full.html"
}