@article {brown1994multivariate,
	title = {Multivariate spatial interpolation and exposure to air pollutants},
	journal = {Canadian Journal of Statistics},
	volume = {22},
	number = {4},
	year = {1994},
	pages = {489{\textendash}509},
	publisher = {Wiley Online Library},
	author = {Brown, Philip J and Le, Nhu D. and Zidek, James V}
}
