@article{LiXu2006,
  author    = {Xianhua Li and Mingyao Xu},
  title     = {The primitive permutation groups of degree 2(a)center dot 3(b)},
  doi       = {10.1007/s00013-005-1494-8},
  url       = {http://www.springerlink.com/content/101192},
  year      = {2006},
}