Kendall, M. G. (1969). "Studies in the History of Probability and Statistics, XXI. The Early History of Index Numbers". Revue de l'Institut International de Statistique / Review of the International Statistical Institute. 37 (1): 1–12. doi:10.2307/1402090. JSTOR1402090.
Kendall, M. G. (1969). "Studies in the History of Probability and Statistics, XXI. The Early History of Index Numbers". Revue de l'Institut International de Statistique / Review of the International Statistical Institute. 37 (1): 1–12. doi:10.2307/1402090. JSTOR1402090.