The Poisson distribution. This is the discrete probability distribution of a number of events occurring in a fixed interval if these events occur with a known average rate, and occur independently from each other within that interval.

• Loader, C. (2000) Fast and Accurate Computation of Binomial Probabilities. http://projects.scipy.org/scipy/raw-attachment/ticket/620/loader2000Fast.pdf * Adell, J., Lekuona, A., and Yu, Y. (2010) Sharp Bounds on the Entropy of the Poisson Law and Related Quantities http://arxiv.org/pdf/1001.2897.pdf