@article {Crai:nonp:2007,
	title = {Nonparametric Regression Methods for Longitudinal Data Analysis. Mixed-effects Modeling Approaches: Hulin Wu and Jin-Ting Zhang},
	journal = {Journal of the American Statistical Association},
	volume = {102},
	number = {478},
	year = {2007},
	pages = {761{\textendash}761},
	author = {Crainiceanu, C}
}
