@conference {HirschVava,
	title = {Exponential lower bounds for finding Brouwer fixed points},
	booktitle = {Proceedings 28th Symposium on Foundations of Computer Science},
	year = {1987},
	pages = {401{\textendash}-410},
	publisher = {IEEE Computer Society Press},
	organization = {IEEE Computer Society Press},
	author = {M. D. Hirsch and S. A. Vavasis}
}