  
  
  [1XReferences[101X
  
  [[20XOPS98[120X]  [16XOpgenorth,  J.,  Plesken, W. and Schulz, T.[116X, [17XCrystallographic Algorithms and Tables[117X, [18XActa Cryst. A[118X, [19X54[119X (1998),
  517--531.
  
  
  
  [32X
