参考文献

Bailly, Jacques; Hertel, Cornelia; Hunziker, Daniel; Lerner, Christian; Obst Sander, Ulrike; Peters, Jens-Uwe; Pflieger, Philippe; Schulz-Gasch, Tanja Patent: US2009/88425 A1, 2009 ; Location in patent: Page/Page column 26 ; US 20090088425 A1