参考文献:
D Sidocky, Neil R. Harris, Roy L. Hegde, Sayee G. Hilgraf, Robert McCarrick, Margaret A. McKie, Jeffrey A. Mortensen, Deborah S. Nadolny, Lisa Perin-Ninkovic, Sophie M. Sapienza, John J. Wright, Jonathan L. Patent: US008/4694 A1, 008 Location in patent: Page/Page column 7 US 00804694 A1