@article {swihart2008quantitative,
	title = {Characterizing Sleep Structure Using the Hypnogram},
	journal = {Journal of Clinical Sleep Medicine, PMCID: PMC2542492},
	volume = {4},
	number = {4},
	year = {2008},
	pages = {349{\textendash}355},
	author = {Swihart, B and Caffo, B and Bandeen-Roche, K and Punjabi, N}
}
