@article{Wu2007,
	title = {A computationally efficient method for nonlinear mixed-effects models with nonignorable missing data in time-varying covariates},
	author = {Lang Wu},
	day = {01},
	journal = {Computational Statistics \& Data Analysis},
	month = {Feb},
	number = {5},
	pages = {2410--2419},
	url = {http://www.sciencedirect.com/science/article/B6V8V-4KNV6GT-2/1/c207d64e39187aa112f616c305328294},
	volume = {51},
	year = {2007},
	biburl = {http://www.bibsonomy.org/bibtex/26db59ca3f7646f4230ffe8f235cc0bf0/smicha},
	keywords = {EM algorithm }
}