@article {MR2876279,
    AUTHOR = {Puno{\v{s}}evac, Predrag and Wang, Qiudong},
     TITLE = {Regularization of simultaneous binary collisions in some
              gravitational systems},
   JOURNAL = {Rocky Mountain J. Math.},
  FJOURNAL = {The Rocky Mountain Journal of Mathematics},
    VOLUME = {42},
      YEAR = {2012},
    NUMBER = {1},
     PAGES = {257--283},
      ISSN = {0035-7596},
     CODEN = {RMJMAE},
   MRCLASS = {70F10},
  MRNUMBER = {2876279},
MRREVIEWER = {Khalil Zare},
       DOI = {10.1216/RMJ-2012-42-1-257},
       URL = {http://dx.doi.org/10.1216/RMJ-2012-42-1-257},
}