@article {MR2532162,
    AUTHOR = {Gao, X. S. and Van der Hoeven, J. and Yuan, C. M. and Zhang,
              G. L.},
     TITLE = {Characteristic set method for differential-difference
              polynomial systems},
   JOURNAL = {J. Symbolic Comput.},
  FJOURNAL = {Journal of Symbolic Computation},
    VOLUME = {44},
      YEAR = {2009},
    NUMBER = {9},
     PAGES = {1137--1163},
      ISSN = {0747-7171},
   MRCLASS = {12H05 (12H10)},
  MRNUMBER = {2532162 (2010g:12006)},
MRREVIEWER = {Alexander B. Levin},
       DOI = {10.1016/j.jsc.2008.02.010},
       URL = {http://dx.doi.org/10.1016/j.jsc.2008.02.010},
}