@article{optimalsubsamplingapproachesforlarge,
  title = {Optimal Subsampling Approaches for Large Sample Linear Regression},
  author = {Rong Zhu and Ping Ma and Michael W. Mahoney and Bin Yu},
  year = {2015},
  eprint = {1509.05111},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1509.05111v2},
}