@article {24936,
	title = {ACM International Conference Proceeding Series},
	journal = {Time{\textquoteright}s up: Studying leaderboards for engaging punctual behaviour},
	year = {2013},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84905507404\&partnerID=MN8TOARS},
	author = {Costa, J.P. and Wehbe, R.R. and Robb, J. and Nacke, L.E.}
}
