  
  
  [1XReferences[101X
  
  [[20XBBN+78[120X]   [16XBrown,   H.,  Bülow,  R.,  Neubüser,  J.,  Wondratschek,  H.  and
  Zassenhaus,  H.[116X,  [17XCrystallographic  Groups  of  Four-Dimensional Space[117X, John
  Wiley, New York (1978).
  
  [[20XHah95[120X] ([1m[31mHahn, T.[15X, Ed.), [17XInternational Tables for Crystallography, Volume A,
  Space-group Symmetry[117X, Kluwer, 4th edition, Dordrecht (1995).
  
  [[20XNPW81[120X]  [16XNeubüser,  J.,  Plesken,  W.  and  Wondratschek,  H.[116X, [17XAn emendatory
  discursion on defining crystal systems[117X, [18XMatch[118X, [19X10[119X (1981), 77--96.
  
  
  
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