http://en.wikipedia.org/wiki/Compound_interest

http://www.moneychimp.com/calculator/compound_interest_calculator.htm

http://math.ucsd.edu/~wgarner/math4c/textbook/chapter4/compoundinterest.htm

http://math.about.com/library/weekly/aa042002a.htm

http://www.answers.com/topic/compound-interest-2

http://math.about.com/od/formulas/a/compound.htm

http://www.moneychimp.com/articles/finworks/fmfutval.htm

http://www.mathsisfun.com/money/compound-interest.html

http://www.webmath.com/compinterest.html

http://www.math.hawaii.edu/~ramsey/CompoundInterest.html