参考文献

Berthel, Steven Joseph; Kester, Robert Francis; Murphy, Douglas Eric; Prins, Thomas Jay; Ruebsam, Frank; Tran, Chinh Viet; Vourloumis, Dionisios Patent: US2008/146625 A1, 2008 ; Location in patent: Page/Page column 20 ; US 20080146625 A1