参考文献:
Gunzner, Janet L. Sutherlin, Daniel Stanley, Mark S. Bao, Liang Castanedo, Georgette M. Lalonde, Rebecca L. Wang, Shumei Reynolds, Mark E. Savage, Scott J. Malesky, Kimberly Dina, Michael S. Patent: US006/6779 A1, 006 Location in patent: Page/Page column 66 78