@inproceedings{theellogonpatternenginecontextfree,
  title = {The Ellogon Pattern Engine: Context-free Grammars over Annotations},
  author = {Georgios Petasis},
  year = {2014},
  booktitle = {LREC 2014 5},
  url = {https://aclanthology.org/L14-1043},
}