@InProceedings{cao21question,
  author = 	"Cao, Shuyang
		and Wang, Lu",
  title = 	"Controllable Open-ended Question Generation with A New Question Type Ontology",
  booktitle = 	"Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics",
  year = 	"2021",
  publisher = 	"Association for Computational Linguistics"
}