1. Armstrong, J.S. 1985. Long-Range Forecasting: From Crystall Ball to Computer, 2nd ed. New York, NY: John Wiley.
2. Barclay, George W. 1958. Techniques of Population Analysis. Wiley.
3. Batie, Sandra. 1989. Sustainable development: challenges to the profession of agricultural economics. American Journal of Agricultural Economics, 1,083–1,101.
4. Bowley, A.L. 1924. Birth and population in Great Britain. The Economic Journal 34: 188–192.
5. Cannan, E. 1895. The probability of a cessation of the growth of population in England and Wales during the next century. The Economist Journal 5: 506–515.