@article {pmid20089508,
	title = {Fast methods for spatially correlated multilevel functional data},
	journal = {Biostatistics},
	volume = {11},
	number = {2},
	year = {2010},
	month = {Apr},
	pages = {177{\textendash}194},
	author = {Staicu, A. M. and Crainiceanu, C and Carroll, R. J.}
}
