@misc{partridge2009determining,
    author = "Partridge, Kurt E and Kunze, Kai and Chu, Maurice K",
    title = "DETERMINING USER COMPASS ORIENTATION FROM A PORTABLE DEVICE",
    year = "2009",
    month = "September\textasciitilde 3",
    publisher = "Google Patents",
    note = "US Patent App. 12/553,839"
}