@article {Caff:Swih:Crai:Laff:Punj:an:2009,
	title = {An Overview of Observational Sleep Research with Application to Sleep State Transitioning},
	journal = {Chance},
	volume = {22},
	number = {1},
	year = {2009},
	pages = {10{\textendash}15},
	author = {Caffo, B and Swihart, B and Crainiceanu, C and Laffan, A and Punjabi, Naresh}
}
