@inproceedings{estimationoptimizationandparallelismwhen,
  title = {Estimation, Optimization, and Parallelism when Data is Sparse},
  author = {John Duchi and Michael. I. Jordan and Brendan Mcmahan},
  year = {2013},
  booktitle = {NeurIPS 2013 12},
  url = {http://papers.nips.cc/paper/4939-estimation-optimization-and-parallelism-when-data-is-sparse},
}