@article{JMLR:v17:15-339,
  author  = {Nahum Shimkin},
  title   = {An Online Convex Optimization Approach to Blackwell's Approachability},
  journal = {Journal of Machine Learning Research},
  year    = {2016},
  volume  = {17},
  number  = {129},
  pages   = {1--23},
  url     = {http://jmlr.org/papers/v17/15-339.html}
}