Description  Claims  Drawing  Cited references 

GB1197414A   [0007] 
GB930627A   [0007] 
WO0006846A   [0007] 
WO0034588A   [0008] 
DE4204497   [0011]  [0011] 
GB1536684A   [0011]  [0012] 
US3581450A   [0011]  [0014] 
US20010008060A   [0011]  [0015] 
GB128556A   [0011] 
GB1285556A   [0016]  [0017] 
WO0106071A1   [0022]