参考文献:
Berthel, Steven Joseph Brinkman, John A. Hayden, Stuart Haynes, Nancy-Ellen Kester, Robert Francis McDermott, Lee Apostle Qian, Yimin Sarabu, Ramakanth Scott, Nathan Robert Tilley, Jefferson Wright Patent: US2009/24445 A, 2009 Location in patent: Page/Page column 57