参考文献:
Branum, Shawn T. Colburn, Raymond W. Dax, Scott L. Flores, Christopher M. Jetter, Michele C. Liu, Yi Ludovici, Donald Macielag, Mark J. Matthews, Jay M. McNally, James J. Reaney, Laura M. Russell, Ronald K. Qin, Ning Teleha, Christopher Wells, Kenneth M. Youells, Scott C. Youngman, Mark A. Patent: US1/1967 A1, 1 Location in patent: Page/Page column 87