@unpublished{publication-8117,
	author={Ledoit, Olivier and Wolf, Michael},
	institution={University of Zurich},
	issn={1664-7041},
	number=122,
	pages=63,
	series={Working paper series / Department of Economics},
	title={Optimal estimation of a large-dimensional covariance matrix under Stein’s loss},
	year=2017,
}