  
  
  [1XReferences[0X
  
  [[20XAlp97[15X]  [16XAlp,  M.[15X,  [17XGAP,  crossed  modules, cat1-groups: applications of
  computational group theory[15X, University of Wales, Bangor (1997)
  
  [[20XAW00[15X]  [16XAlp,  M.  and  Wensley, C. D.[15X, [17XEnumeration of cat1-groups of low
  order[15X, [18XInt. J. Algebra and Computation[15X, [19X10[15X (2000), 407--424
  
  [[20XBro82[15X]   [16XBrown,   R.[15X   ([1m[31mBrown,   R.   and   Thickstun,   T.  L.[15X,  Ed.),
  [17XHigher-dimensional  group theory[15X, in Low-dimensional topology, Cambridge
  University  Press,  London  Math.  Soc.  Lecture Note Series, [19X48[15X (1982),
  215--238
  
  [[20XBH78[15X]  [16XBrown,  R.  and  Higgins,  P.  J.[15X, [17XOn the connection between the
  second  relative  homotopy  group  and some related spaces[15X, [18XProc. London
  Math. Soc.[15X, [19X36[15X (1978), 193--212
  
  [[20XBL87[15X]  [16XBrown, R. and Loday, J. -.L.[15X, [17XVan Kampen theorems for diagram of
  spaces[15X, [18XTopology[15X, [19X26[15X (1987), 311--335
  
  [[20XBW95[15X]  [16XBrown, R. and Wensley, C. D.[15X, [17XOn finite induced crossed modules,
  and  the  homotopy  2-type  of mapping cones[15X, [18XTheory and Applications of
  Categories[15X, [19X1[15X (1995), 54--71
  
  [[20XBW96[15X]  [16XBrown,  R. and Wensley, C. D.[15X, [17XComputing crossed modules induced
  by  an  inclusion  of  a  normal subgroup, with applications to homotopy
  2-types[15X, [18XTheory and Applications of Categories[15X, [19X2[15X (1996), 3--16
  
  [[20XBW03[15X]  [16XBrown,  R.  and  Wensley,  C.  D.[15X,  [17XComputation  and homotopical
  applications  of  induced  crossed  modules[15X, [18XJ. Symbolic Computation[15X, [19X35[15X
  (2003), 59--72
  
  [[20XEll84[15X]   [16XEllis,  G.[15X,  [17XCrossed  modules  and  their  higher  dimensional
  analogues[15X, University of Wales, Bangor (1984)
  
  [[20XES87[15X] [16XEllis, G. and Steiner, R.[15X, [17XHigher dimensional crossed modules and
  the homotopy groups of (n+1)-ads.[15X, [18XJ. Pure and Appl. Algebra[15X, [19X46[15X (1987),
  117--136
  
  [[20XGil90[15X]  [16XGilbert, N. D.[15X, [17XDerivations, automorphisms and crossed modules[15X,
  [18XComm. in Algebra[15X, [19X18[15X (1990), 2703--2734
  
  [[20XLod82[15X]  [16XLoday,  J.  L.[15X,  [17XSpaces with finitely many non-trivial homotopy
  groups[15X, [18XJ. App. Algebra[15X, [19X24[15X (1982), 179--202
  
  [[20XMoo01[15X]  [16XMoore,  E.  J.[15X,  [17XGraphs  of  Groups: Word Computations and Free
  Crossed Resolutions[15X, University of Wales, Bangor (2001)
  
  [[20XNor87[15X]  [16XNorrie, K. J.[15X, [17XCrossed modules and analogues of group theorems[15X,
  King's College, University of London (1987)
  
  [[20XNor90[15X]  [16XNorrie,  K.  J.[15X,  [17XActions and automorphisms of crossed modules[15X,
  [18XBull. Soc. Math. France[15X, [19X118[15X (1990), 129--146
  
  [[20XWhi48[15X]  [16XWhitehead,  J. H. C.[15X, [17XOn operators in relative homotopy groups[15X,
  [18XAnn. of Math.[15X, [19X49[15X (1948), 610--640
  
  [[20XWhi49[15X]  [16XWhitehead,  J.  H.  C.[15X,  [17XCombinatorial homotopy II[15X, [18XBull. Amer.
  Math. Soc.[15X, [19X55[15X (1949), 453--496
  
  
  
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