@inproceedings{CHI-2005-ChellapillaLSC,
	author        = "Kumar Chellapilla and Kevin Larson and Patrice Y. Simard and Mary Czerwinski",
	booktitle     = "{Proceedings of the 23rd ACM SIGCHI Conference on Human Factors in Computing Systems}",
	doi           = "10.1145/1054972.1055070",
	isbn          = "1-58113-998-5",
	pages         = "711--720",
	publisher     = "{ACM}",
	title         = "{Designing human friendly human interaction proofs (HIPs)}",
	year          = 2005,
}