@article{Arag�n1992,
	title = {Existence and uniqueness of the maximum likelihood estimator for
	the two-parameter negative binomial distribution},
	author = {Jorge Arag{\'o}n and David Eberly and Shelly Eberly},
	day = {08},
	journal = {Statistics \& Probability Letters},
	month = {Dec},
	number = {5},
	pages = {375--379},
	url = {http://www.sciencedirect.com/science/article/B6V1D-4BWKWG0-9/1/6c94dc4e5e6c95fb1990145a6318dfb8},
	volume = {15},
	year = {1992},
	biburl = {http://www.bibsonomy.org/bibtex/2003370dd92aa42863f5171a1fdd875ee/smicha},
	keywords = {Maximum estimator likelihood }
}