Double groupoids and crossed modules

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1. 1 J. Benabou, Introduction to bicategories, Lecture Notes in Math.47, Sprin ger (1967), 1-77. MR220789
2. 2 R. Brown, Elements of modern topology, Mc Graw Hill, Maidenhead, 1968. Zbl0159.52201MR227979
3. 3 R. Brown and P.J. Higgins, On the connections between the second relative homotopy groups of some related spaces, Proc. London Math. Soc. (to appear). Zbl0405.55015MR478150
4. 4 R. Brown and C.B. Spencer, Double groupoids, G-groupoids and crossed sequences, Preliminary Report, November 1972. Zbl0344.18004
5. 5 W.H. Cockcroft, On the homomorphisms of sequences, Proc. Cambridge Phil. Soc.45 (1952), 521- 532. Zbl0048.02102MR50883
6. 6 C. Ehresmann, Catégories et Structures, Dunod, Paris, 1965. Zbl0192.09803MR213410
7. 7 J.W. Gray, Formal category theory: adjointness for 2-categories, Lecture Notes in Math.391, Springer (1974), 1- 282. Zbl0285.18006MR371990
8. 8 P.J. Higgins, Categories and groupoids, Van Nostrand, New-York, 1971. Zbl0226.20054MR327946
9. 9 S. Mac Lane, Categories for the working mathematician, Springer, Berlin, 1971. Zbl0232.18001MR354798
10. 10 S. Mac Lane and J.H.C. Whitehead, On the 3-type of a complex, Proc. Nat. Acad. Sci., Washington36 (1950), 41-48. Zbl0035.39001
11. 11 J. Virsik, On the holonomity of higher order connections, Cahiers Topo. et Géo. Diff.XII (1971), 197-212. Zbl0223.53026MR305294
12. 12 J.H.C. Whitehead, Combinatorial homotopy II, Bull. A. M. S.55 (1949), 453-496. Zbl0040.38801MR30760
13. 13 O. Wyler, Multiple functor categories (preprint), Carnegie- Mellon, 1972. 
14. 14 G.M. Kelly and R. Street, Review of the elements of 2-categories, Lecture Notes in Math.420 (1974), 75 - 103. Zbl0334.18016MR357542
15. 15 R. Brown and C.B. Spencer, G-groupoids, crossed modules and the fundamental groupoid of a topological group, Proc. Kon. Ned. Akad. Wet.A79 (1976), 296. Zbl0333.55011MR419643

1. Christopher B. Spencer, An abstract setting for homotopy pushouts and pullbacks
2. Ronald Brown, Philip J. Higgins, The equivalence of $\infty$-groupoids and crossed complexes
3. Timothy Porter, Crossed modules in $Cat$ and a Brown-Spencer theorem for $2$-categories
4. C. B. Spencer, Y. L. Wong, Pullback and pushout squares in a special double category with connection
5. Robert Dawson, Robert Pare, General associativity and general composition for double categories
6. R. J. M. Dawson, R. Pare, D. A. Pronk, Free extensions of double categories