@conference {zhang_chi12,
	title = {Human Computation Tasks with Global Constraints: A Case Study},
	booktitle = {Proceedings of the ACM Conference on Human Factors in Computing (CHI{\textquoteright}12)},
	year = {2012},
	pages = {217-226},
	url = {http://econcs.seas.harvard.edu/files/econcs/files/zhang_chi12.pdf},
	author = {Haoqi Zhang and Edith Law and Robert C. Miller and Krzysztof Z. Gajos and David C. Parkes and Eric Horvitz}
}
