参考文献:
Zahn, Stephan Karl Boehmelt, Guido Mantoulidis, Andreas Reiser, Ulrich Treu, Matthias Guertler, Ulrich Schoop, Andreas Solca, Flavio Tontsch-Grunt, Ulrike Brueckner, Ralph Reither, Charlotte Herfurth, Lars Kraemer, Oliver Stadtmueller, Heinz Engelhardt, Harald Patent: US27/3254 A, 27 Location in patent: Page/Page column 8 US 273254 A