4 October 2005 http://rasmusen.org There is some confusion over what exactly Zermelo proved. To sort it out, see the references below. The Schwalbe and Walker article also has the translation that appears in the Reader. Schwalbe, Ulrich and Paul Walker, "Zermelo and the Early History of Game Theory," Games and Economic Behavior, vol. 34, no. 1, January 2001, pp. 123-37. Working paper version at http://www.math.harvard.edu/~elkies/FS23j.03/zermelo.pdf. http://www-groups.dcs.st- and.ac.uk/~history/Projects/MacQuarrie/Chapters/Ch4.html http://crookedtimber.org/2004/09/08/trembling-hands Martin showed that infinite perfect-information zero-sum games are determined in most cases, Annals of Mathematics 102, 1975. Christian Ewerhart’s 2002 "Backward Induction and the Game-Theoretic Analysis of Chess", Games and Economic Behavior 39, 206-212.