@article {welch_construction_1990,
	title = {Construction of permutation tests},
	journal = {Journal of the American Statistical Association},
	volume = {85},
	number = {411},
	year = {1990},
	pages = {693{\textendash}698},
	url = {http://amstat.tandfonline.com/doi/abs/10.1080/01621459.1990.10474929},
	author = {Welch, William J.}
}
