@article {homcat,
    AUTHOR = {Gaucher, P.},
     TITLE = {Homotopy invariants of higher dimensional categories and
              concurrency in computer science},
      NOTE = {Geometry and concurrency},
   JOURNAL = {Math. Structures Comput. Sci.},
  FJOURNAL = {Mathematical Structures in Computer Science. A Journal in the
              Applications of Categorical, Algebraic and Geometric Methods
              in Computer Science},
    VOLUME = {10},
      YEAR = {2000},
    NUMBER = {4},
     PAGES = {481--524},
      ISSN = {0960-1295},
   MRCLASS = {55U35 (18G55 68Q85)},
  MRNUMBER = {MR1786472 (2001e:55026)},
}