Paper  bibtex   

@article{ryall_identity-differentiating_2006,
	title = {Identity-differentiating widgets for multiuser interactive surfaces},
	volume = {26},
	url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1683694},
	number = {5},
	urldate = {2016-05-05},
	journal = {Computer Graphics and Applications, IEEE},
	author = {Ryall, Kathy and Esenther, Alan and Forlines, Clifton and Shen, Chia and Shipman, Sam and Morris, Meredith Ringel and Everitt, Katherine and Vernier, Frederic D.},
	year = {2006},
	note = {00021},
	pages = {56--64}
}