preference

References

1: Charles Bouton, Nim, a game with a complete mathematical theory. Ann of math.,Princeton,3. 1901-2.
2: Michael H. Albert, Richard J. Nowakowski and David Wolfe, Lessons In Play , A K Peters.
3: Richard K. Guy, Fair Game, Comap's Explorations in Mathematics.
4: A.C.Robin, A poisoned chocolate problem, Problem corner, The Mathematical Gazette Volume 73 1989.
5: Colin Rose, The Distribution of the Knight, Theoretical Research Institute, http://www.tri.org.au/knightframe.html
6: The On-Line Encyclopedia of Integer Sequences,
http://www.research.att.com/ njas/sequences/