参考文献

Berthel, Steven Joseph; Kester, Robert Francis; Murphy, Douglas Eric; Prins, Thomas Jay; Ruebsam, Frank; Sarabu, Ramakanth; Tran, Chinh Viet; Vourloumis, Dionisios Patent: US2008/21032 A1, 2008 ; Location in patent: Page/Page column 79 ; US 20080021032 A1