参考文献

Andersen, Knud Erik; Dorwald, Florencio Zaragiza; Peschke, Bernd; Sidelmann, Ulla Grove; Rudolf, Klaus; Stenkamp, Dirk; Hurnaus, Rudolf; Muller, Stephan Georg; Krist, Bernd; Eriksen, Birgitte Patent: US2002/58659 A1, 2002 ; US 20020058659 A1