@article {Crai:Caff:Di:Punj:nonp:2009,
	title = {Nonparametric Signal Extraction and Measurement Error in the Analysis of Electroencephalographic Activity During Sleep},
	journal = {Journal of the American Statistical Association},
	volume = {104},
	number = {486},
	year = {2009},
	pages = {541{\textendash}555},
	keywords = {Hierarchical smoothing, Measurement error, penalized splines, Sleep},
	author = {Crainiceanu, C and Caffo, B and Di, Chong-Zhi and Punjabi, Naresh M}
}
