Description  Claims  Cited references 

US4980053A   [0006] 
US6210562B   [0006] 
EP0922744A   [0006] 
WO0218516A1   [0007] 
US5294332A   [0008] 
EP0381870A   [0009] 
AU776247   [0010] 
US4658081A   [0011] 
EP0355928A   [0012] 
US4265787A   [0013] 
WO9708268A   [0014]