@article {bai2016activity,
	title = {An activity index for raw accelerometry data and its comparison with other activity metrics},
	journal = {PloS ONE},
	volume = {11},
	number = {8},
	year = {2016},
	pages = {e0160644},
	publisher = {Public Library of Science},
	author = {Bai, Jiawei and Di, Chongzhi and Xiao, Luo and Evenson, Kelly R and LaCroix, Andrea Z and Crainiceanu, Ciprian M and Buchner, David M}
}
