1. Karl Pearson, II. Mathematical contributions to the theory of evolution. II. Skew variation in homogeneous material, Proceedings of the Royal Society of London, Vol.57, pp.257–260, 1885.
2. Karl Pearson, III. Contributions to the mathematical theory of evolution, Philosophical Transactions of the Royal Society A, Mathematical, Physical and Engineering Science, Vol.185, pp.71–110, 1894.
3. Karl Pearson, X. On the criterion that a given system of deviations from the probable in the case of a correlated system of variables is such that it can be reasonably supposed to have arisen from random sampling, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, Vol.50, No.302, pp.157–175, 1900.
4. D. R. Cox, Biometrika: The First 100 Years, Biometrika, Vol.88, No.1, pp.3–11, 2001.
5. E. S. Pearson, Karl Pearson: An appreciation of some aspects of his life and work, Biometrika, Vol.28, No.3/4, pp.193–257, 1936.