@booklet {rubin1965approximations,
	title = {Approximations to the distribution function of sums of independent chi random variables},
	number = {106, Nonr-225 (52)},
	year = {1965},
	publisher = {Department of Statistics, Stanford University},
	address = {Stanford, California},
	author = {Rubin, Herman and Zidek, James V.}
}
