@inproceedings{ahierarchicaltaxonomyforclassifying,
  title = {A hierarchical taxonomy for classifying hardness of inference tasks},
  author = {Martin Gleize and Brigitte Grau},
  year = {2014},
  booktitle = {LREC 2014 5},
  url = {https://aclanthology.org/L14-1119},
}