参考文献:
Yu, Guixue Ewing, William R. Mikkilineni, Amarendra B. Pendri, Annapurna Sher, Philip M. Gerritz, Samuel Ellsworth, Bruce A. Wu, Gang Huang, Yanting Sun, Chongqing Murugesan, Natesan Gu, Zhengxiang Wang, Ying Sitkoff, Doree Johnson, Stephen R. Wu, Ximao Patent: US5/13381 A1, 5 Location in patent: Page/Page column 9