
@phdthesis{A1,
author             = "M.~Alp",
title              = "GAP, crossed modules, cat1-groups:
                      applications of computational group theory",
type               = "Ph.{D}.~thesis", 
year               = "1997",
school             = "University of Wales, Bangor",
}

@article{AW1,
author             = "M.~Alp and C.~D.~Wensley",
title              = "Enumeration of cat1-groups of low order",
journal            = "Int. J. Algebra and Computation", 
volume             = "10",
pages              = "407--424", 
year               = "2000",
}

@inproceedings{B82,
author             = "R.~Brown",
title              = "Higher-dimensional group theory",
booktitle          = "Low-dimensional topology", 
series             = "London Math. Soc. Lecture Note Series", 
volume             = "48",
editor             = " R.~Brown and T.~L.~Thickstun",
publisher          = "Cambridge University Press", 
year               = "1982", 
pages              = "215--238",
}

@article{BH1,
author             = "R.~Brown and P.~J.~Higgins",
title              = "On the connection between the second relative 
                      homotopy group and some related spaces",
journal            = "Proc. London Math. Soc.", 
volume             = "36",
pages              = "193--212", 
year               = "1978",
}

@article{BW1,
author             = "R.~Brown and C.~D.~Wensley",
title              = "On finite induced crossed modules, 
                      and the homotopy $2$-type of mapping cones",
journal            = "Theory and Applications of Categories",
volume             = "1",
pages              = "54--71", 
year               = "1995",
}

@article{BW2,
author             = "R.~Brown and C.~D.~Wensley",
title              = "Computing crossed modules induced by an 
                      inclusion of a normal subgroup, 
                      with applications to homotopy $2$-types",
journal            = "Theory and Applications of Categories",
volume             = "2",
pages              = "3--16", 
year               = "1996",
}

@article{BW3, 
author             = "R.~Brown and C.~D.~Wensley",
title              = "Computation and homotopical applications 
                      of induced crossed modules", 
journal            = "J. Symbolic Computation",
volume             = "35",
year               = "2003", 
pages              = "59--72",
} 

@phdthesis{E1,
author             = "G.~Ellis",
title              = "Crossed modules and their higher dimensional analogues",
type               = "Ph.{D}.~thesis", 
school             = "University of Wales, Bangor", 
year               = "1984",
}

@article{G1,
author             = "N.~D.~Gilbert",
title              = "Derivations, automorphisms and crossed modules",
journal            = "Comm. in Algebra",
volume             = "18",
pages              = "2703--2734", 
year               = "1990",
}

@article{L1,
author             = "J.~L. Loday",
title              = "Spaces with finitely many non-trivial homotopy groups",
journal            = "J. App. Algebra", 
volume             = "24",
pages              = "179--202", 
year               = "1982",
}

@phdthesis{M1,
author             = "E.~J.~Moore",
title              = "Graphs of Groups:
                      Word Computations and Free Crossed Resolutions",
type               = "Ph.{D}.~thesis", 
school             = "University of Wales, Bangor", 
year               = "2001",
}

@phdthesis{N2,
author             = "K.~J.~Norrie",
title              = "Crossed modules and analogues of group theorems",
type               = "Ph.{D}.~thesis", 
school             = "King's College, University of London", 
year               = "1987",
}

@article{N1,
author             = "K.~J. Norrie",
title              = "Actions and automorphisms of crossed modules",
journal            = "Bull. Soc. Math. France", 
volume             = "118",
pages              = "129--146", 
year               = "1990",
}

@article{W2,
author             = "J.~H.~C.~Whitehead",
title              = "On operators in relative homotopy groups",
journal            = "Ann. of Math.", 
volume             = "49",
pages              = "610--640", 
year               = "1948",
}

@article{W1,
author             = "J.~H.~C.~Whitehead",
title              = "Combinatorial homotopy {I}{I}",
journal            = "Bull. Amer. Math. Soc.", 
volume             = "55",
pages              = "453--496", 
year               = "1949",
}
