This article is first published in this series.
MSC 2000: 18G50, 18G99, 18B25, 18D30, 18D35, 18G30, 18F10
Keywords: bouquets and gerbs, non-abelian 2-cocycles, theory of descent
Published 2013-04-03 in:
Reprints in Theory and Applications of Categories,
No. 23 (2013) pp. 1-165