@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.} }