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Some publications in non-abelian homological and homotopical algebra

This Bibliography lists some papers and books on multiple categories and groupoids, non-linear homological algebra, and related areas directly relevant to the themes developed in the accompanying article on Higher dimensional group theory.

The list is not complete, and should be thought of more as an entry point into the literature. It is hoped to develop it over time. The paper "Some problems in non abelian homological and homotopical algebra" gives some 35 problems or problem areas in this field.

I have given a separate and fuller bibliography on the non abelian tensor product.

This bibliography should be related to papers on Lie groupoids, Lie algebroids and Lie pseudoalgebras in a bibliography compiled by Kirill Mackenzie.

Papers added in 2004 are coloured brown.

September 25, 2008  The subject is advancing so much that it is not possible for me to keep this list up to date. See also the n-category cafe and the ncatlab.

  1. R.Aboughazi, `Produit tensoriel du groupe d'Heisenberg', Bull. Soc. Math. France, 15, 95-106, 1987.
  2. G. Abramson, J.-P.Meyer, J.Smith, `A higher dimensional analogue of the fundamental groupoid', in Recent developments of algebraic topology, RIMS Kokyuroku 781, Kyoto, 38-45, 1992.
  3. F.Al-Agl, Aspects of multiple categories, University of Wales PhD Thesis, 1989.
  4. F.Al-Agl and R.J.Steiner, `Nerves of multiple categories', Proc. London Math. Soc., 66, 92-128, 1992.
  5. F.Al-Agl, R. Brown  and R.J.Steiner, `Multiple categories: the equivalence between a globular and cubical approach', Advances in Mathematics, 170 (2002) 71-118. pdf
  6. M. Alp and C.D. Wensley, Enumeration of cat1-groups of low order (97.05), IJAC (to appear).
  7. Z. Arvasi and T. Porter, Simplicial and Crossed Resolutions of Commutative Algebras, J Algebra, 181, 1996, 426-448.
  8. Z. Arvasi and T. Porter, Higher dimensional Peiffer elements in Simplicial Commutative Algebras, Theory and Applications of Categories, 3 (1997) 1-23.
  9. N.Ashley, Simplicial T-complexes, University of Wales PhD Thesis, 1976, published as Simplicial T-complexes: a non-abelian version of a theorem of Dold-Kan, Diss. Math. 165, 11-58 (1988).
  10. M.F. Atiyah, `Mathematics in the 20th century', Bulletin London Math. Soc. 34 (2002) 1-15.
  11. M.R.Bacon, `On the non-abelian square of a nilpotent group of class 2', Glasgow Math. J. 36 (1994) 291-297.
  12. M.R.Bacon, L.-C. Kappe, `The non-abelian square of a 2-generator $p$-group of class 2', Arch. math., 61 (1993) 508-516.
  13. J. C. Baez, J.Dolan, `Higher-dimensional algebra and topological quantum field theory', Jour. Mat. Physics 36 (1995) 6073-6105.
  14. J. Baez and M. Neuchl, `Higher dimensional algebra I: Braided monoidal 2-categories', Adv. Math. 121 (1996) 196-244.
  15. J. C. Baez, J.Dolan, `Higher-dimensional algebra III: n-categories and the algebra of Opetopes', Riverside Preprint, February, 1997.
  16. Y.-G. Baik, J.Howie, S.J.Pride, `The identity problem for graph products of groups', J. Algebra 162 (1993) 168-177.
  17.  I. C. Baianu, R. Brown, G. Georgescu, and J. F. Glazebrook, `Complex nonlinear biodynamics in categories: higher dimensional algebra, and Lukasiewicz--Moisil Topos: transformations of neuronal, genetic and neoplastic networks', Axiomathes (to appear) 57 pages. UWB Preprint 05.13
  18. J.Barja, C.Rodriguez, `Homology groups and eight term exact sequences', Cah. Top. Géom. Diff. Cat. 31, 91-120, 1990.
  19. H.J.Baues, Algebraic homotopy, Cambridge University Press, 1989.
  20. H.J.Baues, Combinatorial homotopy and 4-dimensional complexes, De Gruyter, 1991.
  21. H.J.Baues, `Homotopy types', in Handbook of algebraic topology, ed. I. M. James, 1995, 78 pp.
  22. H.J.Baues, D.Conduché, `The central series for Peiffer commutators in groups with operators', J.Algebra, 133, 1-34, 1990.
  23. H.J.Baues, D.Conduché, `The tensor algebra of a non-Abelian group', K-theory, 5, 531-554, 1992.
  24. H.J.Baues, R.Brown, `On the relative homotopy groups of the product filtration and a formula of Hopf', J. Pure Appl. Algebra 89, 49-61, 1993.
  25. H. J. Baues, A. Tonks, `On the twisted cobar construction', Math. Proc. Camb. Phil. Soc., 121 (1997) 229-245.
  26. W.A.Bogley, M.A.Gutierrez, `Mayer-Vietoris sequences in homotopy of 2-complexes and in homology of groups', J. Pure Appl. Algebra 77, 39-65, 1992.
  27. W.A. Bogley, S.J.Pride, `Aspherical relative presentations', Proc. Edinburgh. Math. Soc. 35 (1992) 1-39.
  28. L.Breen, `Bitorseurs et cohomologie non-Abélienne', The Grothendieck Festschrift: a collection of articles written in honour of the 60th birthday of Alexander Grothendieck, Vol. I, edited P.Cartier, et al., Birkhauser, Boston, Basel, Berlin, 401-476, 1990.
  29. L.Breen, `Théorie de Schreier supérieure', Ann. Sci. écol. Norm. Sup. 25 (1992) 465-514.
  30. R.Brown, `Groupoids and Van Kampen's theorem', Proc. London Math. Soc. (3) 17, 385-401, 1967. pdf
  31. R. Brown, Topology: a geometric account of general topology, homotopy types and the fundamental groupoid, Ellis Horwood, Chichester, (1988) (first edition, McGraw Hill, 1968). Republished privately as `Topology and Groupoids' Booksurge, 2006.
  32. R.Brown, `On the second relative homotopy group of an adjunction space: an exposition of a theorem of J.H.C.Whitehead', J. London Math. Soc. (2) 22, 146-152, 1980.
  33. R.Brown, `Higher dimensional group theory', in Low-dimensional topology, ed. R.Brown and T.L.Thickstun, London Math. Soc. Lect. Notes 46, Cambridge University Press, 215-238, 1982.
  34. R. Brown, `Non-abelian cohomology and the homotopy classification of maps' , in Homotopie alg\'ebrique et algebre locale, Conf. Marseille-Luminy 1982, ed. J.-M. Lemaire et J.-C. Thomas, Ast\'erisques 113-114 (1984), 167-172.
  35. R. Brown, `Coproducts of crossed $P$-modules: applications to second homotopy groups and to the homology of groups', Topology 23, 337-345, 1984.
  36. R.Brown, `From groups to groupoids: a brief survey', Bull. London Math. Soc., 19, 113-134, 1987. pdf
  37. R.Brown, Elements of Modern Topology, McGraw Hill, Maidenhead, 1968; Topology: a geometric account of general topology, homotopy types and the fundamental groupoid, Ellis Horwood, Chichester, 1988.   new edition
  38. R.Brown, `Triadic Van Kampen theorems and Hurewicz theorems', Proc. Int. Conf. Algebraic Topology, Evanston, 1988 ed. M.Mahowald, Cont. Math. 96, 113-134, 1989.
  39. R.Brown, `Some problems in non-Abelian homological and homotopical algebra', Homotopy theory and related topics: Proceedings Kinosaki, 1988, Edited M.Mimura, Springer Lecture Notes in Math. 1418, 105-129, 1990. pdf
  40. R.Brown, `$q$-perfect groups and universal $q$-central extensions', Publicacions Mat. 34, 291-297, 1991.
  41. R.Brown, `Computing homotopy types using crossed $n$-cubes of groups', Proc. Adams Memorial Symposium on Algebraic Topology, Manchester 1990, Volume I, ed N.Ray and G. Walker, London Math. Soc. Lecture Note Series 175, Cambridge University Press, 187-210, 1991. pdf
  42. R.Brown, `Homotopy theory, and change of base for groupoids and multiple groupoids', Applied Categorical Structures 4 (1996) 175-193. pdf
  43. R. Brown, `Representation and computation for crossed modules', Proceedings Catégories, Algebres, Esquisses, Neo-esquisses, Caen, 1994, 6pp.
  44. R. Brown, `Groupoids and crossed objects in algebraic topology', Homology , homotopy and applications, 1 (1999) 1-78.
  45. R. Brown, `Crossed complexes and homotopy groupoids as non commutative tools for higher dimensional local-to-global problems', Proceedings of the Institute Workshop on Categorical Structures for Descent and Galois Theory, Hopf Algebras and Semiabelian Categories, September 23-28, Fields Institute Communications 43 (2004) 101-130. UWB Math Preprint 02.26 (30 pp). pdf
  46. R. Brown, M. Dyer, `The homotopy classification of maps of crossed complexes', (in preparation).
  47. R. Brown and G. J. Ellis, `Hopf formulae for the higher homology of a group', Bull. London Math. Soc., 20 (1988) 124-128. erratum
  48. R.Brown, N.D.Gilbert, `Algebraic models of 3-types and automorphism structures for crossed modules', Proc. London Math. Soc. (3) 59, 51-73, 1989. pdf
  49. R.Brown, M.Golasinski, `A model structure for the homotopy theory of crossed complexes', Cah. Top. Géom. Diff. Cat. 31, 61-82, 1989. pdf
  50. R.Brown, M.Golasinski, T. Porter, A. Tonks, `Spaces of maps into classifying spaces for equivariant crossed complexes', Indag. Math. 8 (1977) 157-172.
  51. R.Brown, M.Golasinski, T. Porter, A. Tonks, `Spaces of maps into classifying spaces for equivariant crossed complexes II: The general topological group case', Preprint number 98.15. 29pp. K-Theory 23 (2001)129-155.
  52. R.Brown, P.J.Higgins, `On the connection between the second relative homotopy groups of some related spaces', Proc. London Math. Soc. (3), 36, 193-212, 1978. pdf
  53. R.Brown, P.J.Higgins, `Sur les complexes croises, $\omega$-groupoides, et T-complexes', C R Acad Sci Paris Ser A 285 (1977) 997-999.
  54. R.Brown, P.J.Higgins, `Sur les complexes croises d'homotopie associee a quelque espaces filtree', C R Acad Sci Paris Ser A 286 (1978) 233-260.
  55. R.Brown, P.J.Higgins, `The equivalence of $\omega$-groupoids and cubical $T$-complexes', Cah. Top. Géom. Diff. 22, 349-370, 1981. pdf
  56. R.Brown, P.J.Higgins, `The equivalence of $\infty$-groupoids and crossed complexes', Cah. Top. Géom. Diff. 22, 371-386, 1981. pdf
  57. R.Brown, P.J.Higgins, `The algebra of cubes', J. Pure Appl. Algebra, 21, 233-260, 1981. pdf
  58. R.Brown, P.J.Higgins, `Colimit theorems for relative homotopy groups', J. Pure Appl. Algebra, 22, 11-41, 1981. pdf
  59. R.Brown, P.J.Higgins, `Crossed complexes and non-abelian extensions', Category theory proceedings, Gummersbach, 1981, Lecture Notes in Math. 962 (ed. K.H. Kamps et al, Springer, Berlin), 39-50, 1982.
  60. R.Brown, P.J.Higgins, `Tensor products and homotopies for $\omega$-groupoids and crossed complexes', J. Pure Appl. Algebra, 47, 1-33, 1987. pdf
  61. R.Brown, P.J.Higgins, `Crossed complexes and chain complexes with operators', Math. Proc. Camb. Phil. Soc. 107, 33-57, 1990. pdf
  62. R.Brown, P.J.Higgins, `The classifying space of a crossed complex', Math. Proc. Camb. Phil. Soc. 110, 95-120, 1992.
  63. R.Brown, P.J.Higgins, `Cubical abelian groups with connections are equivalent to chain complexes', Homology, Homotopy and Applications, 5(1) (2003) 49-52.
  64. R.Brown, J. Huebschmann, `Identities among relations', in Low-dimensional topology, ed. R.Brown and T.L.Thickstun, London Math. Soc. Lect. Notes 46, Cambridge University Press, 153-202, 1982.
  65. R. Brown, I. Icen, `Homotopies and automorphisms of crossed modules of groupoids', Applied Categorical Structures, 11 (2003) 185-206. pdf
  66. R. Brown, I. Icen, `Towards a 2-dimensional notion of holonomy', Advances in Math, 178 (2003) 141-175. pdf
  67. R.Brown, G. Janelidze, ` Van Kampen theorems for categories of covering morphisms in lextensive categories', J. Pure Appl. Algebra 119 (1997) 255-263.
  68. R.Brown, G. Janelidze, `Galois theory of second order covering maps of simplicial sets', J. Pure Appl. Algebra, 135 (1999) 83-91.
  69. R.Brown, G. Janelidze, `Galois Theory and a new homotopy double groupoid of a map of spaces', Applied Categorical Structures 12 (2004) 63-80.
  70. R.Brown, D.L.Johnson, E.F.Robertson, `Some computations of non-abelian tensor products of groups', J. Algebra, 111, 177-202, 1987.
  71. R. Brown, K.H. Kamps, and T. Porter , `A homotopy double groupoid of a Hausdorff space II: a van Kampen theorem', Theory and Applications of Categories, Vol. 14, (2005) 200-220. 
  72. R.Brown, J.-L.Loday, `Excision homotopique en basse dimension', C.R. Acad. Sci. Ser. I. Math. Paris, 298 (1984) 353-356.
  73. R.Brown, J.-L.Loday, `Van Kampen theorems for diagrams of spaces', Topology, 26, 311-335, 1987. pdf
  74. R.Brown, J.-L.Loday, `Homotopical excision, and Hurewicz theorems, for $n$-cubes of spaces', Proc. London Math. Soc. (3), 54, 176-192, 1987. pdf
  75. R.Brown, K.C.H.Mackenzie, `Determination of a double Lie groupoid by its core diagram', J. Pure Appl. Algebra 80, 237-272, 1992. [Here for postscipt file]
  76. R. Brown, G.H. Mosa, `Double categories, 2-categories, thin structures and connections', Theory and Applications of Categories 5 (1999) 163-175.
  77. R.Brown, O.Mucuk, `Covering groups of non-connected topological groups revisited', Math. Proc. Camb. Phil. Soc. 115, 97-110, 1994. pdf
  78. R. Brown, R.Paton and T. Porter, `Categorical language and hierarchical models for cell systems', Computation in Cells and Tissues - Perspectives and Tools of Thought, Paton, R.; Bolouri, H.; Holcombe, M.; Parish, J.H.; Tateson, R. (Eds.) Natural Computing Series, Springer (2004) 289-303.
  79. R. Brown, T. Porter, `The methodology of mathematics', Math. Gazette, (1995).
  80. R. Brown, T. Porter, `On the Schreier theory of non-abelian extensions: generalisations and computations', Proceedings Royal Irish Academy, 96 (1996) 213-227. pdf
  81. R. Brown and T. Porter, `Category theory and higher dimensional algebra: potential descriptive tools in neuroscience', Proceedingsof the International Conference on Theoretical Neurobiology, Delhi, February 2003, edited by Nandini Singh, National Brain Research Centre, Conference Proceedings 1 (2003) 80-92. UWB Preprint 03.05
  82. R. Brown and T. Porter, `Category Theory: an abstract setting for analogy and comparison', Advanced Studies in Mathematics and Logic (to appear) UWB Preprint 05.10 . pdf
  83. R.Brown, A. Razak Salleh, `Free crossed resolutions of groups and presentations of modules of identities among relations', Bangor Preprint 1997, 20pp. LMS J. Comp. and Math. 2 (1999) 28-61.
  84. R.Brown, C.B.Spencer, `Double groupoids and crossed modules', Cah. Top. Géom. Diff., 17, 343-362, 1976. pdf
  85. R.Brown, C.B.Spencer, `$\cal G$-groupoids, crossed modules, and the classifying space of a topological group', Proc. Kon. Akad. v. Wet. 79, 296-302, 1976.
  86. R.Brown, A.Tonks, `Calculation with simplicial and cubical groups in Axiom', J. Symbolic Computation 17, 159-179, 1994.
  87. R.Brown and C.D.Wensley, `On finite induced crossed modules and the homotopy 2-type of mapping cones', Theory Appl. Categories, 3, 54-71, 1995.
  88. R.Brown and C.D.Wensley, `Computing crossed modules induced by an inclusion of a normal subgroup, with applications to homotopy 2-types', Theory Appl. Categories, 2, 3-16, 1996.
  89. R.Brown and C.D.Wensley, `Computation and homotopical applications of induced crossed modules', J. Symbolic Computation 35 (2003) 59-72.
  90. R. A. Brown, ` Generalised group presentations', Trans. Amer. Math. Soc., 334, 519-549, 1992.
  91. M.Bullejos, A.M.Cegarra, J.Duskin, `On cat$^n$-groups and homotopy types', J. Pure Appl. Algebra 86 (1993) 135-154.
  92. M.Bullejos, P. Carrasco, A.Cegarra, `Cohomology with coefficients in symmetric cat$^n$-groups. An extension of Eilenberg-Mac Lane's classification theorem.' Granada Preprint, 1992.
  93. J.S. Carter, M. Saito, `Knotted surfaces, braid movies and beyond', Preprint, University of Texas at Austin, 1993.
  94. Jean-Louis Cathelineau, `Birapport et groupoides', Enseign. Math., II. Ser. 41, No.3-4, 257-280 (1995).
  95. \v{C}ech, E. `H\"{o}herdimensionale homotopiegruppen', Verhandlungen des Internationalen Mathematiker-Kongresses Zurich, Band 2, (1932) 203.
  96. D. Conduché, `Modules croisés généralisés de longeur 2', J. Pure Appl. Algebra, 34 (1984) 155-178.
  97. D. Conduché, G.J.Ellis, `Quelques propriétés homologiques des modules précroisés', J. Algebra, 123, 327-335, 1989.
  98. D.Conduché, C.Rodriguez-Fernandez, `Non-abelian tensor and exterior products and universal $q$-central relative extensions', J. Pure Appl. Algebra 78, 139-160, 1992.
  99. A. Connes, Non commutative geometry, Academic Press, 1994.
  100. J.-M.Cordier, T.Porter, `Fibrant diagrams, rectifications and a construction of Loday', J. Pure Appl. Algebra 67, 111-124, 1990.
  101. J.-M.Cordier, T.Porter, Homotopy Coherent Category Theory, Trans. Amer. Math .Soc. 349 (1997) 1-54.
  102. S.J. Crans, On combinatorial models for higher dimensional homotopies, Doctoral thesis, Utrecht, 1995.
  103. N.K. Dakin, Kan complexes and multiple groupoid structures, University of Wales, Bangor, Ph D Thesis (1997).
  104. A.J.Duncan, G.J.Ellis, N.D.Gilbert, `A Mayer-Vietoris sequence in group homology and the decomposition of relation modules', Glasgow Math. J. 37 (1995) 159-171.
  105. P.J.Ehlers and T. Porter, `From simplicial groupoids to crossed complexes', UCNW Maths Preprint 92.19, 35pp, 1992.
  106. P.J.Ehlers and T. Porter, Varieties of simplicial groupoids I: Crossed complexes, J Pure and Applied Algebra 120 (1997) 221-233.
  107. P.J.Ehlers and T. Porter, Varieties of simplicial groupoids I: Crossed complexes, erratum, J Pure and Applied Algebra 1999, Vol.134, No.2, pp.207-209
  108. G.J.Ellis, `The non-abelian tensor product of finite groups is finite', J. Algebra, 111, 203-205, 1987.
  109. G.J.Ellis, `Non-Abelian exterior products of groups and exact sequences in the homology of groups', Glasgow Math. J., 29, 13-19, 1987a.
  110. G.J.Ellis, `Non-Abelian exterior products of Lie algebras and an exact sequence in the homology of Lie algebras', J. Pure Appl. Algebra, 46, 111-115, 1987c.
  111. G.J.Ellis, `Higher dimensional crossed modules of algebras', J. Pure Applied Algebra, 52, 277-282, 1988.
  112. G.J.Ellis, `Multirelative algebraic $K$-theory: the group$K_2(\Lambda;I_1,\ldots ,I_n)$ and related computations', J. Algebra 112, 271-289, 1988.
  113. G.J.Ellis, `An algebraic derivation of a certain exact sequence', J. Algebra, 127, 178-181, 1989.
  114. G.J.Ellis, `Relative derived functors and the homology of groups', Cah. Top. Géom. Diff. Cat. 31, 121-135, 1990.
  115. G.J.Ellis, `Relative derived contravariant functors and the cohomology of groups', J. Pure Applied Algebra 64 (1990) -33.
  116. G.J.Ellis, `A non-Abelian tensor product of Lie algebras', Glasgow Math. J., 33, 101-120, 1991.
  117. G.J.Ellis, `Crossed squares and combinatorial homotopy', Math. Z., 461 (1993) 93-110.
  118. G.J. Ellis, `Tensor products and q-crossed modules', J. London Math. Soc., (2) 51 (1995) 243-258.
  119. G.J.Ellis, T.Hurley, F.Leonard, `Some computations of the non-abelian tensor product', 7pp, Galway Preliminary Report, 1992.
  120. G.J.Ellis, F.Leonard, `Computing Schur multipliers and tensor products of finite groups', Proc. Royal Irish Acad., 95A (1995) 137-147.
  121. G.J. Ellis, T.Porter, `Free and projective crossed modules and the second homology of a group', J. Pure Applied Algebra, 40, 27-31, 1986.
  122. G.J.Ellis, C. Rodriguez-Fernandez, `An exterior product for the homology of groups modulo $q$', Cah. Top. Géom. Diff. Cat. 30, 339-343, 1989.
  123. G.J.Ellis, R.Steiner, `Higher-dimensional crossed modules and the homotopy groups of $(n+1)$-ads', J. Pure Appl. Algebra, 46, 117-136, 1987.
  124. R.Fenn, C.J.Rourke, B.J.Sanderson, `An introduction to species and the rack space', Warwick Preprint 29/1992, 19pp, (1992).
  125. R.Fenn, C.J.Rourke, B.J.Sanderson, `James bundles, species and the rack space', Warwick Preprint 49/1992, 49pp, (1992).
  126. N.D.Gilbert, `The non-Abelian tensor square of a free product of groups', Arch. Math., 48, 369-375, 1987.
  127. N.D.Gilbert, `The fundamental catn-group of an n-cube of spaces', Proc. Conf. Algebraic Topology, Barcelona, 1986 (ed. J.Aguadé and R.Kane) Springer Lecture Notes in Math. 1298, 124-139, 1988.
  128. N.D.Gilbert, `Identities between sets of relations', J. Pure Appl. Algebra 84 (1993) 263-276.
  129. N.D.Gilbert, P.J.Higgins, `The non-Abelian tensor product of groups and related constructions', Glasgow Math. J., 31, 17-29, 1989.
  130. N.D.Gilbert, J.Howie, `Threshold subgroups for Cockcroft 2-complexes', Preprint Heriot Watt, 1992.
  131. T.Goodwillie, `The calculus of homotopy functors II', $K$-theory 5, 295-332, 1992.
  132. A.Grothendieck, Pursuing stacks, Manuscript, 600pp, (distributed from Bangor) 1983.
  133. A.Grothendieck, private communication, (1985).
  134. D.Guin, `Cohomologie non-Abéliennes des groupes', J. Pure Appl. Algebra, 50, 109-138, 1988.
  135. D. Guin-Walery and J.-L. Loday, `Obstructions a l'excision en K-theorie algebrique', SLNM 854 (1981) 179-216.
  136. T. Hannebauer, `On non-abelian tensor squares of linear groups', Arch. Math. 55 (1990) 30-34.
  137. M. Hartl, `The non-abelian tensor square for groups of class 2', Bielefeld Preprint, 1993, J. Algebra, 179 (1996) 416-440.
  138. P.J. Higgins, `Algebras with a scheme of operators', Math. Nach. 27 (1963) 115-132.
  139. P.J. Higgins, `Presentations of groupoids, with applications to groups', Proc. Camb. Phil. Soc., 60 (1964) 7-20.
  140. P.J. Higgins, Categories and groupoids, TAC  Reprints 7 (2005) pp 1-195.
  141. P.J. Higgins, `Thin elements and commutative shells in cubical omega-categories', Theory and Applications of Categories, Vol. 14, (2005) 60-7
  142. P.J.Higgins, J.Taylor, `The fundamental groupoid and homotopy crossed complex of an orbit space', Category Theory Proceedings, Gummersbach, 1981, Lecture Notes in Math. 962, edited K.H.Kamps et al, Springer, Berlin, pp. 115-122, 1982.\vspace{-0.1in}
  143. C. Hog-Angeloni, W.Metzler, A.J.Sieradski, (Editors), Two-dimensional homotopy and combinatorial group theory, London Math. Soc. Lecture Note Series 197, Cambridge University Press, Cambridge (1993).
  144. J.Howie, `Pullback functors and crossed complexes', Cah. Top. Géom. Diff. Cat. 20, 281-295, 1979.
  145. J.Huebschman, `Crossed $n$-fold extensions and cohomology', Comm. Math. Helv., 55, 302-314, 1980.
  146. N. Innassaridze, `Non abelian tensor products and non-abelian homology of groups', J. Pure Appl. Algebra (to appear).
  147. G. Janelidze, `What is a double central extension?', Cah. Top. Géom. Diff. Cat. 32, 191-201, 1991.
  148. J.F. Jardine, `Categorical homotopy theory' (preprint Waterloo).
  149. D.L.Johnson, `The non-Abelian square of a finite split metacyclic group', Proc. Edinburgh Math. Soc., 30, 91-95, 1987.
  150. D.W.Jones, Polyhedral $T$-complexes, University of Wales PhD Thesis, 1984; published as A general theory of polyhedral sets and their corresponding $T$-complexes, Diss. Math. 266, 1988. pdf of thesis
  151. K.H. Kamps and T. Porter, Abstract homotopy and simple homotopy theory. World Scientific, 462pp (ISBN 981-02-1602-5) June 1997.
  152. L.-C. ,Kappe, `Non abelian tensor products of groups: the commutator connection', Proceedings Groups St Andrews 1997 at Bath, LMS Lecture Notes (to appear).
  153. L.-C. Kappe and M.P Visscher, `Two generator two-groups of class two and their nopn abelian tensor squares', SUNY-Binghampton Preprint, 17 pp, 1998.
  154. M.M.Kapranov, V.Voevodsky, `Combinatorial-geometric aspects of polycategory theory: pasting schemes and higher Bruhat orders (list of results)', Cah. Top. Géom. Diff. Cat. 32, 11-27, 1991.
  155. M.M.Kapranov, V. Voevodsky, `$\infty$-groupoids and homotopy types' Cah. Top. Géom. Diff. Cat. 32, 29-46, 1991.
  156. M.M.Kapranov, V. Voevodsky, `2-categories and Zamolodchikov tetrahedra equations', Proceedings of Symposia in Pure Maths, Amer. Math. Soc. 56, Part 2, 177-259, 1994.
  157. J.-L.Loday, `Spaces with finitely many non-trivial homotopy groups', J. Pure Appl. Algebra, 24, 179-202, 1982.
  158. J.-L. Loday and D. Guin-Walery, `Obstruction a l'excision en K-theorie algebrique', SLNM
  159. J.-H.Lu, A.Weinstein, `Groupoïdes symplectiques doubles des groupes de Lie-Poisson', Compte Rend. Acad. Sci. Paris (à paraitre). Preprint Berkeley, 1989.
  160. A. McDermott, The non abelian tensor product of groups: Computations and structural results, PhD Dissertation, National University of Ireland, Galway, 1998.
  161. K.C.H.Mackenzie, `Classification of principal bundles and Lie groupoids with prescribed gauge group bundle', J. Pure Appl. Algebra 58, 181-208, 1989.
  162. K.C.H.Mackenzie, `Double Lie algebroids and second order geometry, I', Advances in Math., 94 (1992) 180-239.
  163. K.C.H.Mackenzie, `Double Lie algebroids and second order geometry, II', preprint, 1996 (27 pages).
  164. G. W. Mackey, `Ergodic theory and virtual groups', Math. Ann., 166 (1966) 187-207.
  165. I.Moerdijk, J-A Svensson, `Algebraic classification of equivariant homotopy 2-types, I', J. Pure App. Algebra 89 (1993) 187-216.
  166. G.Nan Tie, `A Dold-Kan theorem for crossed complexes' J. Pure Appl. Algebra, 56, 177-194, 1989.
  167. G.Nan Tie, `Iterated $W$ and $T$-groupoids', J. Pure Appl. Algebra, 56, 195-209, 1989.
  168. K.Norrie, `Actions and automorphisms of crossed modules', Bull. Soc. Math. France, 118, 129-146, 1990.
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