@article{Zhao1994b,
	title = {Covariance matrices of quadratic forms in elliptical distributions},
	author = {Yi Zhao},
	day = {23},
	journal = {Statistics \& Probability Letters},
	month = {Sep},
	number = {2},
	pages = {131--140},
	url = {http://www.sciencedirect.com/science/article/B6V1D-45FSPTD-7/1/87fd9f75f6da2b17960b354ba8c0c746},
	volume = {21},
	year = {1994},
	biburl = {http://www.bibsonomy.org/bibtex/2ace6cf57ed186a22fb5b5cf2a89f5375/smicha},
	keywords = {A form generalized quadratic }
}