@inproceedings{thecomplexityoffindingthemaximum,
  title = {The complexity of finding the maximum spanning DAG and other restrictions for DAG parsing of natural language},
  author = {Natalie Schluter},
  year = {2015},
  booktitle = {SEMEVAL 2015 6},
  url = {https://aclanthology.org/S15-1031},
}