@article{JMLR:v14:liu13b,
  author  = {Qiang Liu and Alexander Ihler},
  title   = {Using Symmetry and Evolutionary Search to Minimize Sorting Networks},
  journal = {Journal of Machine Learning Research},
  year    = {2013},
  volume  = {14},
  number  = {99},
  pages   = {303--331},
  url     = {http://jmlr.org/papers/v14/liu13b.html}
}