@conference {huang2020comparative,
	title = {A Comparative study of the relationship between the subjective difficulty, objective difficulty of search tasks and search behaviors},
	booktitle = {Proceedings of the ACM/IEEE Joint Conference on Digital Libraries in 2020},
	year = {2020},
	pages = {421{\textendash}424},
	author = {Kun Huang and Jiaqi Chen and Chang Liu and Zhang, Lulu}
}
