Description  Claims  Drawing  Cited references 

DE3209885   [0008]  [0008] 
DK173159   [0009]  [0009]  [0009]  [0009] 
GB2129286A   [0010]  [0010]  [0010]  [0010] 
EP0568961A   [0010]  [0010] 
GB2070401A   [0010]  [0010]