E.; Wilson, R., Graph Theory, 1736–1936, Oxford University Press, 1986 Cauchy, A. L., Recherche sur les polyèdres - premier mémoire, Journal de l'École
the beans dropping through the quincunx pattern. (页面存档备份,存于互联网档案馆) from Index Funds Advisors IFA.com (页面存档备份,存于互联网档案馆) Stochastic Processes used in Quantitative