@inproceedings{CHI-2015-MeutznerGK,
	author        = "Hendrik Meutzner and Santosh Gupta and Dorothea Kolossa",
	booktitle     = "{Proceedings of the 33rd ACM SIGCHI Conference on Human Factors in Computing Systems}",
	doi           = "10.1145/2702123.2702127",
	isbn          = "978-1-4503-3145-6",
	pages         = "2335--2338",
	publisher     = "{ACM}",
	title         = "{Constructing Secure Audio CAPTCHAs by Exploiting Differences between Humans and Machines}",
	year          = 2015,
}