1. Woytinsky, W. S. and Woytinsky, E. S. 1953.World Population and Production: Trends and Outlook, 350–350. Twentieth Century Fund. and 365
2. France, Statistique Générale. 1902.Statistique annuelle du mouvement de la population, 38 Appendix
3. United Nations. 1953.The Determinants and Consequences of Population Trends48–48.