  
  
  [1XReferences[101X
  
  [[20XHol85[120X]  [16XHolt,  D.  F.[116X,  [17XThe  mechanical  computation  of  first  and second
  cohomology    groups[117X,    [18XJ.    Symb.    Comput.[118X,    [19X1[119X    (1985),    351--361
  (https://doi.org/10.1016/S0747-7171(85)80020-1).
  
  
  
  [32X
