参考文献

Arnold, Norbert; Teichert, Axel; Rosahl, Sabine; Westermann, Bernhard; Wessjohann, Ludger; Eschen-Lippold, Lennart; Draeger, Tobias Patent: US2012/129938 A1, 2012 ; Location in patent: Page/Page column 2; 3; 4-5 ;