参考文献

Andreini, Matteo; Gabellieri, Emanuele; Guba, Wolfgang; Marconi, Guido; Narquizian, Robert; Power, Eoin; Travagli, Massimiliano; Woltering, Thomas; Wostl, Wolfgang Patent: US2009/209529 A1, 2009 ; Location in patent: Page/Page column 34 ;