@article{JMLR:v14:gong13a,
  author  = {Pinghua Gong and Jieping Ye and Changshui Zhang},
  title   = {Multi-Stage Multi-Task Feature Learning},
  journal = {Journal of Machine Learning Research},
  year    = {2013},
  volume  = {14},
  number  = {91},
  pages   = {2979--3010},
  url     = {http://jmlr.org/papers/v14/gong13a.html}
}