@misc{W2051339053,
  author = {Kurt VanLehn},
  title = {The Relative Effectiveness of Human Tutoring, Intelligent Tutoring Systems, and Other Tutoring Systems},
  year = {2011},
  howpublished = {Educational Psychologist},
  doi = {https://doi.org/10.1080/00461520.2011.611369}
}