@article{Wen2007c,
	title = {Optimal sufficient dimension reduction in regressions with categorical
	predictors},
	author = {Xuerong Wen and R. Dennis Cook},
	day = {01},
	journal = {Journal of Statistical Planning and Inference},
	month = {Jun},
	number = {6},
	pages = {1961--1978},
	url = {http://www.sciencedirect.com/science/article/B6V0M-4KR3H6F-1/1/56922aa35cd85d83bfc93c49fef33e71},
	volume = {137},
	year = {2007},
	biburl = {http://www.bibsonomy.org/bibtex/25cdd14cbf344da775ea0435cee5a4c2a/smicha},
	keywords = {Inverse regression }
}