@online{baez/online,
  author       = {Baez, John C. and Lauda, Aaron D.},
  title        = {Higher-Dimensional Algebra {V}: 2-Groups},
  date         = {2004-10-27},
  version      = 3,
  langid       = {english},
  langidopts   = {variant=american},
  eprinttype   = {arxiv},
  eprint       = {math/0307200v3},
}