@article {heckman_minimax_1988,
	title = {Minimax estimates in a semiparametric model},
	journal = {Journal of the American Statistical Association},
	volume = {83},
	number = {404},
	year = {1988},
	pages = {1090{\textendash}1096},
	url = {http://amstat.tandfonline.com/doi/abs/10.1080/01621459.1988.10478706},
	author = {Heckman, Nancy E.}
}
