@article{timevaryinglearningandcontentanalytics,
  title = {Time-varying Learning and Content Analytics via Sparse Factor Analysis},
  author = {Andrew S. Lan and Christoph Studer and Richard G. Baraniuk},
  year = {2013},
  eprint = {1312.5734},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1312.5734v1},
}