Etienne van de Valle (adapted by), from the French section edited by Louis Henry. Fecundity. Multilingual demographic dictionary, English section, second edition. Demopaedia.org, International Union for the Scientific Study of Population: 621-1. 1982 [8 February 2010]. (原始内容存档于2010-02-11).
Etienne van de Valle (adapted by), from the French section edited by Louis Henry. Fecundity. Multilingual demographic dictionary, English section, second edition. Demopaedia.org, International Union for the Scientific Study of Population: 621-1. 1982 [8 February 2010]. (原始内容存档于2010-02-11).