@InProceedings{Reddy/etal/16d,
  title={Unbounded Human Learning: Optimal Scheduling for Spaced Repetition},
  author={Reddy, Siddharth and Labutov, Igor and Banerjee, Siddhartha and Joachims, Thorsten},
  booktitle={Arxiv 1602.07032},
  year={2016},
  url={http://arxiv.org/abs/1602.07032}
}