@Inproceedings{EPTCS93.4,
  author    = {K\"onig, Harald and Wolter, Uwe  and L\"owe, Michael},
  year      = {2012},
  title     = {Characterizing Van Kampen Squares via Descent Data},
  editor    = {Golas, Ulrike and Soboll, Thomas},
  booktitle = {{\rm Proceedings Seventh ACCAT Workshop on}
               Applied and Computational Category Theory ,
               {\rm Tallinn, Estonia, 01/04/2012}},
  series    = {Electronic Proceedings in Theoretical Computer Science},
  volume    = {93},
  publisher = {Open Publishing Association},
  pages     = {61-81},
  doi       = {10.4204/EPTCS.93.4},
}