@unpublished{publication-7826,
	author={Ledoit, Olivier and Wolf, Michael},
	institution={University of Zurich},
	issn={1664-7041},
	number=105,
	pages=40,
	series={Working paper series / Department of Economics},
	title={Spectrum estimation: a unified framework for covariance matrix estimation and PCA in large dimensions},
	year=2013,
}